Criminal Defense Investigations

Keith L. Walker, CCDI

Phone: 413.788.4988
(CPCS certified in MA)

Criminal Defense Investigations:

I have investigated everything from simple A&B, to sex-related charges involving minors, and have led a multi-agency homicide investigation that crossed state lines.
In every case, protecting the innocent from wrongful punishment was always a top priority.

Ultimately, my role is to work to support your client's innocence -or find mitigating factors that reduce the charges.
I'm thorough, creative and tireless about finding the truth and uncovering the facts you need, so you can best defend your client.

defense investigator expert testimony

Thorough, diligent and creative.

I find the witnesses police haven't talked to, and dig up the facts they haven't found by looking in places they haven't looked.

Reasonable Doubt.

Whether showing officers took short-cuts and made errors or omissions or by impeaching the testimony of a witness.

Any court. Anywhere in MA.

From the Berkshires to Cape Cod.
Any district or superior court.
Anywhere in MA.

Interviews and Statements:

25+ years experience conducting interviews and taking written and recorded statements.
I have taken statements with respect to nearly every type of criminal defense case, and hundreds with respect to insurance/SIU claims.
Signed and recorded statements can "lock" in a witnesses testimony.

Statement questions are prepared in advance to assure all relevant lines of inquiry are thoroughly addressed.
Thoroughness in preparation is essential because you may only get -one- chance for an important interview.

Background Checks

What is the victims reputation and character?
Do the significant witnesses have a reputation for dishonesty in the community?
You need to know!

You may need to impeach the testimony of an adverse witness -or assure your best witnesses won't be impeached.
An inquiry into their character can yield the kind of information you'll need, to impeach their testimony.
And get the best outcome for your client.

Locates and Skip-Tracing

Discovery Services Investigations has had great success locating witnesses and other parties.
Even those who prefer not to be found (see Testimonials)

Our resources extend from social media and the web to newspapers, municipal records, and a proprietary database available only to licensed investigators and law enforcement.
In my 30 year career I've managed to amass a list of resources that help locate just about anyone.


Trial preparation and litigation support: Because a "second pair of eyes" can assure you that you haven't missed anything.
There's a lot of value in the confidence you get from being sure of yourself.
Pre-sentence investigations can go a long way to help your client get probation, if convicted.

I can also conduct insurance defense investigation for insurance or SIU matters.
I can conduct accident scene investigations and analysis, surveillance, document retrieval and more.

About DSI

My name is Keith Walker and I started Discovery Services Investigations in 1993.
I'm a licensed private detective and a board certified criminal defense investigator.
I'm one of 5 active board certified investigators in MA. and the only one west of Framingham.

I specialize in criminal defense, by choice.
It's the only kind of work I do.
I'm grateful for the privilege of helping to keep the innocent from being wrongfully punished, and to diligently assist those in need of a good defense investigator.

Attorney Testimonials

MA criminal defense

"As a criminal defense attorney, I have worked with several investigators over the years, and Keith Walker was, by far, the most reliable and thorough investigator that I've worked with.
I recommend his services without hesitation".

Laurence Cohen, Esq.Criminal defense attorney, Springfield, MA

Attorney services

"I would like to thank you for the statement you recently obtained for me relative to the above-mentioned case. The statement was obtained very quickly and in a very professional manner. Additionally, your rates were very reasonable. Again, thank you for your assistance."

Deborah A. Plaia, Esq. Attorney, Mount Holly, NJ


"Keith Walker of Discovery Services has performed investigative services for my clients on a number of occasions in the past. I have found his work to be thorough and of excellent quality. Mr. Walker has always been responsive and has performed excellent investigative work for me in the past."

Christopher J. O'Rourke, Esq. Attorney, Boston, MA

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"I have been a criminal and person injury attorney for almost 20 years. Beginning sometime in 2009 I believe, when the investigator I had previously been using retired, Investigator Keith Walker has and continues to provide exceptional services for our law firm's clients. I would recommend him to anyone in need of an investigator."

Robert J. Rzeszutek Esq, Facchini & Facchini, P.C., Springfield, MA.

happy attorneys

"I am a criminal defense attorney. I have utilized Keith and Discovery Services multiple times over the last four years and have been thoroughly satisfied with his assistance. Keith is very helpful and does excellent work. He also is willing to offer his input during the assignment which helps solidify other avenues to discover within the investigation."

Judy Cox, Esq, Criminal defense attorney, Springfield, MA.


"Keith is a great investigator. Thorough, reliable, and keeps you in the loop. I whole-heartedly recommend him to anyone who needs an investigator"

Matthew Peterson, Esq. Criminal Defense attorney, Boston, MA.

Interviews and statements

"...extraordinarily helpful...I was doubtful that we were ever going to track down this young man. I tried other methods and contacted other private investigators who indicated they were unable to do the assignment. Thank you for taking care of this matter for us and my client thanks you as well."

Kevin Z. Komar Esq. Attorney, Goodman Acker PC, Southfield, MI

Background checks

"I have had the opportunity to hire Mr. Keith Walker to provide private investigative services in connection with matters regarding my clients. Mr. Walker has consistently handled matters in a professional, timely and cost-effective manner. I highly recommend Mr. Walker's investigative services.""

Bonnie Karas, Esq. Attorney, Monson MA


"...diligent, thorough, and on time…extremely helpful in suggesting the most cost and time efficient way to obtain the information sought...cordial and professional at all times"

Mary Jane E. Legal Department, City of Westfield, MA

Contact DSI

Call Discovery Services Investigations any time,
to discuss your investigative needs.

Call: 413.788.4988
Mailing address: PO Box 80131, Springfield MA 01138

"It is more important that innocence be protected than it is that guilt be punished,
for guilt and crimes are so frequent in this world that they cannot all be punished.
But if innocence itself is brought to the bar and condemned, perhaps to die,
then the citizen will say, 'Whether I do good or whether I do evil is immaterial,
for innocence itself is no protection, and if such an idea as that were to take
hold in the mind of the citizen, that would be the end of security whatsoever.' "
John Adams Dec 4, 1770