Sometimes the cops have unrealistic expectations as well
When I worked for a university IT Services department, I was frequently called in to assist the campus police when computers or technical devices were involved in an investigation. They would often ask for things like "Can you tell me whether this individual used this specific computer three weeks ago?" The problem with the request was often that the computer was either a person's privately owned device or a completely public kiosk computer in the library that did not require users to login. They also had the perception that we could magically reconstruct everything a person did while on a computer. Though it might have been technically possible to some extent, we weren't well funded enough to have the tools or time to devote to that level of computer forensics. I must also mention that I had to work with some FBI computer techs when every Solaris server we had was hit with an attack in late fall of 2000. The guy the sent out really knew what he was doing. Luckily for me, I wasn't responsible for the systems that were attacked, but I got to help with the investigation since somebody else was out for a conference or training.
