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May 28, 2013
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Nick Perna Gang Investigations
with Nick Perna

4 tips for success in providing expert gang testimony

Good solid gang testimony at the end of a case can be the “final flurry” needed to get a conviction.

Fans of boxing and mixed martial arts know that most fighters will attempt to do something spectacular in the final 30 seconds of the round to leave a lasting impression on the judges. 

In gang cases, we need to do the same thing with our judges (and juries). 

Good solid gang testimony at the end of a case can be the “final flurry” needed to get a conviction.

Four Keys to Success
A successful gang investigation has many moving parts. The initial, responding officers need to get all the pertinent facts, collect evidence and interview the key players at the scene. Detectives need to conduct follow up interviews, search warrants, and other investigative techniques.  

District Attorneys deal with preparing a successful courtroom strategy. 

Arguably, though, the most important part of a gang case is expert testimony. It is the capstone to the case and will often be the most significant factor that a judge or jury will consider when deciding the outcome of a case.

Unfortunately expert testimony has the most potential pitfalls, not only for the officer but for the case overall. If they aren’t careful, officers expose themselves to attack by savvy defense attorneys looking to exploit weaknesses in testimony. 

In a worst case scenario, an officer’s very credibility (possibly an officer’s most important trait) can become compromised, which can have long-lasting effects.

Here are some of my own recommendations for preparing for gang testimony:

1.) Be a Student of Gangs — It’s not enough to know the ins and outs of the case you’re testifying about. You need to be well versed in gang culture in general, as well as the specifics of the gang you are testifying about. 

When I’m getting ready for a case, I’ll review the pertinent sections of Gangs, by Al Valdez. It’s a great book that’s full of good information. 

It’s also a book used by defense attorneys to test an officer’s knowledge of gang culture.

2.) Do a ‘Cheat Sheet’ — In the jurisdiction where I work, we’re required to write a gang predicate report explaining why the crime is gang related and why the suspects are gang members. These predicate reports run from 10 to 50 pages and have a lot of information in them. 

Unless you want to memorize all if it (I can think of better ways to spend my time), use a cheat sheet. My typical cheat sheet explains — in one or two sentences — why the crime is gang related. It also contains a list of suspect tattoos, a very short list of the suspect’s crimes and a list of his or her gang associates. 

I don’t put anything sensitive or personal on the cheat sheet so, if need be, it can be handed over to the defense if requested. It’s better than flipping through a couple hundred pages of documentation, trying to find an important fact with a judge and jury staring at you. 

3.) Get Everything Done Before You Get to Court — You don’t want to be on the witness stand, looking at your predicate (or, preferably, you cheat sheet) and realize that you don’t recognize a name you have listed as a gang associate of the suspect. 

It sounds rudimentary, but it’s happened to me and I’m going to go out on a limb and say it’s happened to others as well. On more than one occasion, while sitting in the courtroom waiting to testify, I’ve had to text a partner of mine to verify some information that I should have taken care of before I got there. 

A good way to avoid this is making sure you only list vetted information in your report. If your suspect has been contacted with 10 other gang members you can verify, does it make your case any better if you list five more you’re not sure about?

4.) Coordinate with the DA — A good DA will tell you ahead of time what he or she is going to be asking about. Gang investigations can be very broad and there is a lot if information involved. This includes but isn’t limited to:

•    Your experience as a gang investigator
•    Discussion of the gang’s prior history
•    Discussions of gang lifestyle in general
•    Why the crime in questions is a gang crime
•    How does it benefit the gang
•    Why are the suspects considered gang members

The more the DA can narrow the scope of questioning the better. Leave the tough questions for the defense…

Back to my fight analogy: it’s best to be consistent throughout the whole process of executing a gang case. Expert testimony should be the final demonstration of your skill, preparation and prowess in the investigation that supports the work done prior to court. 

You want to do such a complete job that the case is a lock for a conviction. As they say in MMA and boxing, “You don’t want to leave it in the hands of the judges…”

About the Author
Nick Perna is a Detective with the Redwood City Police Department, currently serving on the Street Crime Suppression Team. Detective Perna has testified as an expert in gang and narcotics cases and has served with local, state, and Federal officers on gang and fugitive task forces. He previously served as a paratrooper in the U.S. Army and is a Veteran of Operation Iraqi Freedom.


About the author

Nick Perna is a Police Officer with the Redwood City Police Department in Northern California. He has spent much of his career as a gang and narcotics investigator. He is a member of a Multi-Jurisdictional SWAT Team since 2001 and is currently a Team Leader. He previously served as a paratrooper in the US Army and is a veteran of Operation Iraqi Freedom. He has a Master’s Degree from the University Of San Francisco.

Contact Nick Perna





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