Tool Mark Investigations

Tool marks

Tools are often used by criminals to force entry to premises and can leave behind evidence for the forensic scientist to find.

Two tools of the same kind and made by the same manufacturer may look the same, but through use each tool can acquire differences. It is these differences that make them unique.

Forensic Scientists are able to help the courts convict criminals by matching the marks on tools to those found at crime scenes.


The examination of tool marks, as with other physical evidence, is based on two characteristics – class characteristics and individual characteristics.

Class characteristics are those characteristics that are common to a group of objects. For example, a hammer has a distinctive shape and typical size.

Individual characteristics are those characteristics which are unique to a given object. They are generally as a result of wear and tear or may be caused by isolated incidents during manufacture. For example, you buy a new pair of shoes and as you wear the shoes, over time you will get scratches and gouges on the soles. These marks are unique to your shoes.

Tool Mark Impressions

Caused by the interaction of two objects, tool mark impressions are distinguished in a variety of ways:

Static marks are made when the tool is pressed into a softer material and leaves an impression. A good example is a crow bar being used to force open a window and a subsequent impression is left in the softer surface of the wood. The Forensic Scientist will examine the marks and may be able to identify what type and size of tool caused the damage.

Dynamic marks are made when a tool slides or scratches across a surface. Think of a key being dragged along the side of a car; such an instrument leaves behind a pattern of lines or striations in the metal of the car. The pattern of striations may be enough for the examiner to identify a match with the tool belonging to a suspect.

Cutting marks are a result of pressure being applied at both sides of an object and are often associated with scissors, wire cutters or shears. When used these tools can leave behind marks and striations along the cut edges of the material.

Multi-stroke marks are caused by repetitive action, such as a saw moving back and forth.


The Scene Examiner will examine and photograph the tool marks in situ. If appropriate, the Scene Examiner will remove the object with the marks and take it to the lab for further analysis. If this is not possible they will make a cast of the marks, generally using a silicone rubber.

A tool may be recovered that is suspected to have caused the damage and this will also be taken to the lab for further analysis.

The Forensic Scientist will make test marks using the suspect implement. The test mark and the mark recovered from the crime scene will then be compared.

The Forensic Scientist will examine and compare the striation patterns using the comparison microscope. By comparing and matching the striations the scientist can prove whether the tool is responsible for the impression.

Tools can also have trace evidence, such as paint flakes adhering, or in the case of a human victim, blood or other body fluids. This evidence greatly assists in the investigation of a crime.

Investigators efforts when hired by attorney

Investigators efforts when hired by attorney

Coito v. Superior Court (2012), 54  Cal.4th 480    [dictum discussed witness statements and suggested efforts of investigator must reflect attorney initiative or thoughts]

2,022 Ranch, LLC v. Superior Court (Chicago Title Ins. Co.)
(2003), 113 Cal. App. 4th 1377  [“Chicago Title objected to questions to the adjuster Look concerning her interviews with third parties (the escrow company and the seller’s agent) as part of her investigation. These questions concerned her factual claims investigation and do not constitute attorney-client communications or attorney work product.”]People v. Collie (1981), 30 Cal.3d 43, at p. 59 [“Nobles also persuasively reasons that the privilege should extend not just to the attorney’s work product, but to the efforts of those who work with him to prepare the defense: “At its core, the work-product doctrine shelters the mental processes of the attorney, providing a privileged area within which he can analyze and prepare his client’s case. But the doctrine is an intensely practical one, grounded in the realities of litigation in our adversary system. One of those realities is that attorneys must often rely on the assistance of investigators and other agents in the compilation of materials in preparation for trial. It is therefore necessary that the doctrine protect material prepared by agents for the attorney as well as those prepared by the attorney himself.” (Id. at pp. 238-239 [45 L.Ed.2d at p. 154].) We conclude that the work-product doctrine applies to criminal cases and protects the work product of defense investigators.”]

Rodriquez v. McDonald Douglas (1978), 87 Cal.App.3d 626 at p.647-48

Southern Pacific Co. v. Superior Court (1969), 3 Cal.App.3d 195 at p.198 [ Protected per dictum not disapproved in Kadelbach ]

Mize v. Atchison, Topeka & Santa Fe (1975), 46 Cal.App.3d 436 at p. [Court assumed investigators reports were work product and compared them to expert’s reports but found waiver because the investigator was to testify ]

Brown v. Superior Court (1963), 218 Cal. App.2d 430 at p. 437

Suezaki v. Superior Court (1962), 58 Cal.2d 166, 178 at p. 177 [films taken by investigator hired by attorney solely for trial prep and intended to be confidential are work product but not privileged as a matter of law; court discretion must be exercised with qualified work product ]

William Monroe LPI, CCDI, CFSI


William A. Monroe is the Director of Investigations/Qualified Manager of W.A. Monroe & Associates Security Consulting and Investigations.  Monroe was born in Connecticut, and after graduating high school began a career in the Security Police Career field with the United States Air Force. During his time with the Air Force, he served in several law enforcement and Security capacities including canine handler, trainer, kennel master, Security force supervisor, Patrol supervisor, Desk Sergeant, Federal executive and dignitary protection detail supervisor, Special Investigations Joint Drug Enforcement Team member, Anti-Terrorism response team leader, and Department of Defense vulnerability and risk assessment team leader.  Bill is a diligent and highly skilled Security, Law Enforcement, and Investigations professional with a broad understanding of the criminal justice system. Bill is a consummate professional, with a proven track record investigating criminal, family law, and plaintiff negligence cases.  His passion for the Constitution and the legal process, coupled with his strong desire to seek out the truth in every case are unparalleled.

Bill is a California Licensed Professional Investigator with over 10 years of professional investigative experience, ranging from insurance fraud investigations, felony three strike cases, to capital murder cases.  Bill is an expert in criminal defense investigation and specializes in capital case mitigation, police procedure and use of force, K-9 search and seizure, and K-9 narcotics and explosives detection. He has superior investigative abilities coupled with comprehensive skills in forensic interviewing, forensic photography, crime scene examination, blood spatter detection, recognition, and analysis, and preparing and presenting accurate facts.

          Bill is a Criminal Defense Investigation Training Council (CDITC) board trained and certified Criminal Defense Investigator CCDI.  He is also a CDITC board trained and certified Forensic Science Investigator (CFSI).   He is currently pursuing his certification as a CDITC board trained and certified Forensic Interviewer (CFI-FTER).  Monroe completes 12-24 Continued Learning and Education (CLE) credits per year.
          Bill  serves on the faculty and training advisory board as the CDITC Western Regional Director and is a faculty cadre Instructor for the Criminal Defense Investigation Training Council (CDITC), Center for Investigative Studies.
          He holds an Associates of Science degree (AS) from the Community College Of The Air Force in Police Science/Industrial Security.  He holds a Bachelors of Arts (BA) degree from Ashford University in Social and Criminal Justice.  Bill  is currently pursuing a Masters of Science degree (MS) in Criminal Justice with a specialization in Forensic Science from Ashford University with 22 credits remaining.

Our Responsibility to Mentor


Good Evening defenders!

Our responsibility to teach, and more importantly mentor each other is imperative to upholding the highest standards in Criminal Defense Investigations. How better to encourage dialogue between professional defense investigators and share investigative philosophy, methodology, and principles in our specialty field. One of the things that discouraged me from the specialty of defense investigation in the beginning of my career was the lack of willingness from “Experienced” investigators to mentor me and show me the specifics of defense investigation. I could find any number of investigators that would tell me why they were the best investigator in the state of California, or the best investigator in the country. It was very easy to find investigators that would tell me what a terrible investigator so and so was, and how much better they were than the other guy.

One of my favorite quotes is from Benjamin Franklin he said, “Tell me and I forget, teach me and I may remember, involve me and I learn.” I was fortunate enough early in my decision to focus primarily on defense investigation, to happen across some very good defense investigators that were not only willing to teach me the science of defense investigation, but they helped me to understand the methodology of sound defense investigation. They showed me through example how to conduct my investigations in an organized, methodical, ethically responsible and procedurally sound manner.

Imparting your knowledge, experience, and thought process only makes you better and your peers better investigators. Continuing to challenge each other, teach and learn from each other is paramount in our efforts in maintaining the tradition of intellectual and academic exchange in an atmosphere which emphasizes innovation, and promotes new learning.

So ask yourself. Which type of investigator are you?

CDITC Forensic Science Investigators Academy

Good morning Defenders!

Back to work after an intensive week long certification/training, for my certification as a Certified Forensic Science Investigator (CFSI). The Academy, hosted by the Criminal Defense Investigation Training Councils Center for Investigative Studies (CDITC), was one of the best I have attended. I found the course to be, informative, concise, and interactive and would recommend it to any Licensed Professional Investigator, or Specialty Investigator, who would like to learn the ability to interpret and recognize the need for independent expert analysis, facilitate the efforts of forensic science experts, and incorporate the findings of those experts into the investigative process to advance defense theory development. I am honored and extremely excited to have been invited to become a part of the CDITC Faculty and Training Advisory Board. I feel it is imperative as specialists in our field, that we promote excellence through mentoring, training, peer reviews, seminars, and conferences, promoting expert knowledge and expertise within the discipline of criminal defense investigation. There is an art, and science to this.

However, contrary to what some of us may think, or say to each other, everybody is not good at EVERYTHING. You know the guy or gal, the one who will tell you they are an expert at everything. Surveillance, “I’m an expert”. Backgrounds “I’m an expert”. Domestic, “I’m an expert”. Criminal Defense, “I’m an expert”. I tell people all of the time, I may not know EVERYTING but I know a whole helluva lot of stuff about SOME things. I am an expert in Criminal Defense Investigation; My specialty is capital case mitigation, police procedure and use of force, K-9 search and seizure, and K-9 narcotics and explosives detection. I am a facilitator I can make large scale investigations, with multiple investigators, witnesses, and moving parts go. I can bring a team of different individuals together and galvanize them around a central goal. I am a specialist, a warrior, a gladiator, in search of the truth. Although I cannot be the best at everything, I do have a pool of over 300 CCDI’s in the world stretching from Guam to London at my disposal who are experts in just about anything I will ever need. If I can’t do it I know a Guy, or Gal who can. I also know that the professional Board Certified Criminal Defense Investigator shares my same philosophy, my same methodology, and the need to standardize and develop an investigative philosophy and methodology specific to the discipline of criminal defense investigation. If you are not utilizing your fellow Investigators in your cases, you should be. The goal should always be to provide the client with the MOST comprehensive, impartial, search for the truth we can provide them. Be safe Defenders!



1) The criminal defense investigator will adhere absolutely and unconditionally to the objective and impartial search for truth. He will abstain from involvement in any situation that subverts this professional commitment.


2) The criminal defense investigator will refrain from asserting, in any professional capacity, any beliefs, opinions, or biases regarding any person or situation under investigation, prior to having commenced the investigation. Nor will the investigator permit any pre-established beliefs, opinions, or biases to influence the course of an investigation to be undertaken.


3) The criminal defense investigator should never, as a matter of policy, claim to have attained absolute or conclusive truth regarding the scope of any investigation. As a matter of policy, investigative truths should always remain potentially open to reinterpretation as new facts or theories emerge. In principle the investigative process should remain speculative rather than dogmatic.


4) The criminal defense investigator will be absolutely and unconditionally honest in all reporting to clients. The investigator will make no dishonest representation of any fact, issue, or theory relating to any case for which he is responsible.


5) The criminal defense investigator will be truthful and open in all communication to colleagues and the public, except in so far as such communication may compromise client confidentiality


6) The criminal defense investigator will honor, absolutely and unconditionally the confidentiality guaranteed to every client, supervisor, or colleague.


7) The criminal defense investigator will not violate any law during the performance of his professional responsibilities.


8) The criminal defense investigator will refrain from any professional activity that jeopardizes health or safety of another person.


9) The criminal defense investigator will refrain from any commitment that entails any inappropriate conflict of interest.


10) The criminal defense investigator will not engage in the unauthorized practice of law or represent himself/herself as a law enforcement officer.

Thank You!

I am honored and privileged to accept my certification as a Board Certified Criminal Defense Investigator from The Criminal Defense Investigation Training Council Center for Investigative Studies (CDITC). Today I am honored to join the ranks of only 8 in the state, and 300 nationally, of the finest public defender investigators and private investigators in the nation. I feel rejuvenated, fresh, and ready to continue to absolutely, and unconditionally, pursue the objective and impartial search for truth! It was a special treat to have the National Director of the CDITC, my esteemed colleague, and friend Brandon Perron award my CCDI to me personally at the ELITE training in Campbell California this weekend. I would also like to thank the great folks at the (California Association Of Licensed Investigators (CALI) Cris Reynolds the President, C.W. Sellers the East Bay coordinator, for having my wife and I. If that was not enough I also had the distinct pleasure as one of my first duties as a CCDI, to present Ms. Francie Koehler another colleague that I admire and respect, who is also the host of the radio show PI’s Declassified, her CCDI board certification from the CDITC. I am ready more than ever to protect and defend the constitution and my client’s rights to fair trial under the law, defending the 6th Amendment one case at a time!


(a) Defense counsel should conduct a prompt investigation of the circumstances of the case and explore all avenues leading to facts relevant to the merits of the case and the penalty in the event of conviction.  The investigation should include efforts to secure information in the possession of the prosecution and law enforcement authorities. The duty to investigate exists regardless of the accused’s admissions, or statements to defense counsel of facts constituting guilt or the accused’s stated desire to plead guilty. The Importance of Prompt Investigation


©2013 Brian S. Batterton, Attorney, PATC Legal & Liability Risk Management Institute (

On May 16, 2013, the Tenth Circuit Court of Appeals decided Hennix v. Prickett et al. [i] which serves as a reminder about when the use of a TASER is considered reasonable under the Fourth Amendment. At the outset, it must be noted that some facts of this case are in dispute and the court was required to view the facts in a light most favorable to the plaintiff in this case, as the defendant officers were making a motion to dismiss the suit based on qualified immunity.

The incident began when an officer stopped Hennix for speeding. Upon observing signs of driving under the influence, the officer had Ms. Hennix exit her car and perform the horizontal gaze nystagmus test, which indicated that she may be impaired. The officer then asked her to perform additional tests, and she advised that should was physically unable to do so because of a back injury. At this point, the officer arrested Ms. Hennix for DUI and had her sit in the back of the police car. Hennix, who claimed to be claustrophobic, then began yelling and banging her head on the window. She claimed she did so because she was claustrophobic and was trying to get the officers’ attention. At this point, the officers decided that they needed to secure Hennix with a hobble and Officer Prickett opened the back door. It is at this point where the officers’ and Hennix’s recollection of the facts differ. Hennix asserts that the officers told her to put her legs out of the car and she told them she was physically incapable of doing so. She asserts that the officers never attempted to pull or lift her legs out of the car but rather Tased her in drive-stun mode for failing to comply with their verbal commands. The officers allege that Hennix never told them that she was physically incapable of putting her legs out of the car and that they did, in fact, attempt to pull her legs out but she had wedged her feet under the front seat to frustrate their efforts. At this point, one of the officers Tased Hennix’s leg in drive-stun mode.

The district court denied the officer’s motion for qualified immunity based upon the fact that under the plaintiff’s version of events, a jury could conclude that the officers used excessive force. The officers appealed to the Tenth Circuit Court of Appeals.

Upon a review of the all the facts and evidence in the case, the Tenth Circuit found that there was evidence to support the Hennix’s version of events. The court stated:

[T]he record reveals sufficient evidence for a jury to conclude Roosevelt-Hennix informed the officers she was physically unable to comply with their request to move her feet outside the patrol vehicle. It likewise contains sufficient evidence for a jury to conclude the officers never attempted to aid Roosevelt-Hennix in moving her feet before applying the taser. [ii]

Consequently, the court held, if a jury believed her version of events, then they could conclude that it was excessive force to use a Taser in drive-stun mode for merely refusing to put her legs out of the car (passive resistance) when ordered to do so where the officers made no attempt to physically remove her legs from the car after having knowledge of a medical condition that made it impossible for her to comply.

What we can learn from this case

1. Officers should consider a person’s ability to comply with commands prior to utilizing a Taser. This ability to comply may be the result of a medical condition, injury sustained while engaged with officers, or as the result of numerous Taser cycles.

2. In circumstances of mere passive resistance where there is no threat to the officers, a Taser is not an appropriate force option.

3. As always, in use of force case, officers should consider the three factors from

Graham v. Connor. The three factors are: (1) the seriousness of the crime at issue, (2) whether the suspect poses a threat to the officer or others, and (3) whether the suspect is actively resisting or attempting to evade arrest by flight.


Note: Court holdings can vary significantly between jurisdictions. As such, it is advisable to seek the advice of a local prosecutor or legal adviser regarding questions on specific cases. This article is not intended to constitute legal advice on a specific case.



[i] No. 12-1307, 2013 U.S. App. LEXIS 9809 (10th Cir. Decided May 16, 2013)

[ii] Id. at 22-23