Of course, every child pornography case is different and who the State will case is dependent upon the facts of the case, the possible defenses and the personal style of the prosecutor. Nevertheless, there are some patterns that emerge. In no real order, the State may call the following witnesses in a typical child pornography P2P trial:
Case agent, lead detective, initial detective, undercover detective
Whatever you want to call this person, he/she is the person that was in charge of the initial downloading process although they may have had limited involvement at the time of the arrest. Typically, they will search for the child pornography, download it from the client, prepare and send out subpoenas and then prepare the search warrant. They may not actually execute the search warrant or have any other involvement after that except for possibly a supervisory role. However, during their testimony they may testify as a non-expert on how a P2P program works. In the end, this witness will be a big nothing as they will not have any interaction with the client and this fact should be brought out in a number of ways on cross. I will not detail them here however.
If the undercover detective does not participate in the execution of the search warrant, two other detectives will likely take over the case from there. Along with over a dozen other officers from a SWAT type unit, they will execute the search warrant, collect the computer(s) and bring the client down to a local police station to be questioned. While short of doing the good cop bad cop routine, these officers will question the client and it should all be recorded.
This may be the most important witness(es) as these detectives helped to determine who will be interviewed, what will be asked, etc. The defense attorney needs to get very creative with cross examination here.
Witness with regard to return on search warrant
A minor witness may be a chain of custody witness that drafted the return on the search warrant and transported seized equipment from one place or another. Sometimes, both sides can stipulate to the documents that the witness would introduce to avoid pointless testimony.
Prior to any search warrant, there is at least one detective that performs serveillance on the premises about to be raided. This witness was normally never called as there was no real testimony at issue here. However, the State is now making it a point to verify whether or not there was an open wi-fi signal outside of the defendant’s house/business thus attempting to foreclose this defense at trial. As a result, this witness will likely come to trial more often in the future. Of course, there are ways to attack this witness.
Computer Forensics Technician
Perhaps the State’s star witness. This is the person that will put it all together. This is also the person that may show the files to the jury (but not always). Despite this witnesses extensive training and experience, the State may not qualify this witness as an expert. This may limit the witness in what he or she can say. The defense attorney should have a brief on this issue ready to go to be faxed to the Court or to at least make an oral argument. I don’t like handing a Court a ready made brief as it makes it clear that you anticipated the argument.
Don’t let the witnesses (likely) nerdy appearance fool you. They are out to bury your client and they are trained in how to testify and how to respond to cross examination. Thus, questions must be very carefully scripted. They will do anything they can to get around your questions. Your job is to nail them down and not let them escape. Most of the witnesses have a script and if you can get them off script, they may quickly crumble. This is where computer forensics knowledge is vital. I cannot see how a defense attorney can spar with such a witness if they cannot speak the lingo and understand the concepts. This witness will likely try to use their superior knowledge to pull a fast one on everyone. Don’t let it happen! A skilled cross examiner and quickly turn this witness into one of the best tools for the defense.