i just had catherine cryer and zack carter on. and they said this would have to be auto thhenticateauthenticate. you both have testified in court and have had to do these kind of testimonies at trials, is that correct? >> yes, sir. >> that's absolutely correct. >> how does it work? tell me how it works, tom. >> well, the authentication process is an examination process. in this instance, the tapes came from the 911 system, which is the law enforcement system. so -- and nobody said the tapes were not authenticated. but we can conduct an examination on the original tapes, should they be provided to us from the 911 call center. >> ed, your experience in courts, and what kind of experiences have you had in terms of cross-examinations you feel you would be able, if you were to be called if there is a trial here to deal with why you have come to this conclusion. >> reverend, we're forensic experts that are on a legal team involved in a litigation. it's our job to bring out whatever clues that we can find from the recordings to the team