in most crime thrillers there is one police officer that is the main person involved, which there will be in our film. this reminds me of 'prisoners' starring Hugh jackman who is looking for his missing daughter and Jake Gyllenhaal who plays the cop that gets too involved in the case. 
http://www.hollywoodreporter.com/news/prisoners-trailer-hugh-jackman-searches-560825
i think it would be a good idea to have a main cop involved as there would be more than one point of view other than the main character.