Surprisingly, and quite often, I find that attorneys are not acting soon enough on cases involving security camera surveillance video. That failure to respond in a timely manner means that video may be automatically erased by the security video recording system before anyone can locate, save, and transfer the important evidence from the hard drives onto a more permanent storage medium that we can then enhance and analyze in our forensic video and audio lab.
Many security systems automatically erase footage after 2 weeks, but some save the material for a month or more. It depends on the system. So be careful!