This documentary series following the Homicide Squad in Indianapolis, in the USA, is essential viewing for me. You really see how they go about their job, and they never seem to accept anything at face value. Most of their cases they solve but never in the allotted hour long spot of fictional cops, and they do not get obsessive over cases. The "stars" include Lt. Kevin Kelly, Sgt Jeff Breedlove, Jessie Beavers, Tom Tudor, Lesia Moore, Cameron Brosseau, Schied, Rice, Lappin & Christine Minka.
What is surprising is just how much information is fed to them, usually by telephone. Kind of slaps down the usual guff "The Wall of Silence". A real good case was one that started out as a missing person report in a neighbouring county; the case was taken up by Moore & Minka. They developed a prime suspect but he refused to give up anything. Minka was ready to travel back to Indy (I think they were in Wisconsin) but Moore and a local detective gave it one last shot. Moore got him to confess and he even drew a map on where to find the victim. The body was where he said it was.
The message these people send out to criminals and killers is that they will not give up. During one investigation, Minka did more work on a cold case and she got a result! They also do not forget the victims families, giving updates on how they are doing. These people do give a positive feel for Law Enforcement in the States.