You can record. Just don't let the cops know, and check your state laws. Currently there are 9 states that have put laws on the books that makes recording police under any circumstances illegal, unless you have their express permission. Some of them have no limits on maximum sentences for these crimes, so be careful. usually people in these states get ten times the punishment for recording cops as it is for whatever crime they have been arrest for in the first place. (Correction, mostly "crime")