Witness Development and Interviews | Criminal Defense Investigation


A witness is someone who has, or claims to have, or is thought by someone with authority to compel testimony, or to have knowledge relevant to an event or other matter of interest. In law, a witness is someone who, either voluntarily or under compulsion, provides testimonial evidence, either oral or written, of what he or she knows or claims to know about the matter before some official authorized to take such testimony. Witnesses can be a very tricky lot.

Inter-State Investigative Services has earned its great reputation, in part, by being able to find previously unknown witnesses, as well as being able to obtain testimony from witnesses that change the course of a case. Witness development requires a wide range of skills, while effectively interviewing witnesses necessitates a different skillset. Fortunately for defense attorneys in southern Arizona, we have these skills and have honed them well over the years.


Investigators who are not adept at finding people might as well be weathermen. When it comes to criminal defense it is even more imperative for an investigator to be able to find any and all witnesses to an alleged crime. Inter-State Investigative Services takes immense pride in our ability to locate witnesses. Because of advances in technology, rare are the occasions when we cannot find a witness.

When it comes to locating witnesses, our capabilities reach far beyond the borders of Arizona. Our techniques and resources run deep. And our stamina is the envy of other investigators. Revealing how we find previously unknown, or seemingly lost witnesses, is not something we’re going to share here, but rest assured our track record speaks for itself. And while we’re not going to give away our trade secrets, we pride ourselves on keeping defense counsel fully in the proverbial loop on our progress with locating any and all witnesses who have even the slightest tangential connection to the case at hand.

WHAT THEY SEE (or smell, hear, etc.) IS WHAT YOU GET

Whether friendly, neutral, or hostile, witnesses often make or break a case. Attorneys don’t need us to break down the differences between varying types of witnesses. But counsel who haven’t worked with us sometimes want to know we know the differences.

Here’s a cursory overview of the main types of witnesses we deal with while investigating on behalf of the defense:

Eyewitness (or Percipient Witness): Someone who testifies what they perceived through his or her senses (e.g. seeing, hearing, smelling, touching). That perception might be either with the unaided human sense or with the aid of an instrument, e.g., microscope or stethoscope, or by other scientific means.

Hearsay Witness: Someone who testifies what someone else said or wrote. In most court proceedings there are many limitations on when hearsay evidence is admissible. Such limitations do not apply to grand jury investigations, many administrative proceedings, and may not apply to declarations used in support of an arrest or search warrant. Also, some types of statements are not deemed to be hearsay and are not subject to such limitations.

Expert Witness: Someone who allegedly has specialized knowledge relevant to the matter of interest, which knowledge purportedly helps to either make sense of other evidence, including other testimony, documentary evidence, or physical evidence (e.g., a fingerprint or handwriting). An expert witness may or may not also be a percipient witness, as in a doctor, or may or may not have treated the victim of an accident or crime.

Character Witness: Someone who testifies about the reputation of a person or business entity, when reputation is material to the dispute at issue. There are different situations where a “character witness” may be called and we are happy to discuss this with defense counsel and/or their staff.


Surprises in court are akin to surprises in one’s shorts: no one likes them and there’s a lot you can do to prevent them. Our investigators approach every witness interview with forethought towards the reliability of the witness, the credibility and relevance of the testimony, and how the testimony can impact the case for the defense. We always keep in mind the big picture of the case and any special instructions or needs counsel may have.

We also are quite adept at putting witnesses at ease. Professionalism, courtesy, and that sine qua non that is essential when interacting with someone who knows something important about a criminal case. This is especially important when investigating a case where a sex crime is alleged. Years of interviewing all ranges of ages and all types of personalities give us an edge over other investigators.

Whether friendly, neutral, or hostile, our approach and techniques for interviewing a witness morph with the particular challenge at hand. That said, our standards for how an interview must be conducted in order to gather legally admissible testimony never waiver. We also keep an eye on how the prosecution’s side of the case is unfolding and steadfastly maintain open communication with defense counsel. In other words, we do everything within our power to get to the truth at hand while eliminating any surprises from witnesses.

If you’re looking for Southern Arizona’s most experienced criminal defense investigators who are masters at locating and/or interviewing witnesses for your case, please click the “Submit a Request” button at the top of the page, or call IISAZ at (520) 882-2723 or (602) 358-7759 immediately.