When Friday examines the gun that Carl used to commit suicide he says " a .38 Colt." But the revolver he picks up and unloads is very clearly identifiable as a .38 Smith and Wesson. It's odd that Friday handled the gun which would corrupt any other fingerprints that might be on it.
After leaving the home of the suicide, Friday says that he and Gannon went back to the office at 1:37 AM. The camera shows their car pulling into the station in the dark, but their were no headlights or taillights illuminated on the car.
The window glass shatters after Friday barely taps on it with his flashlight; so it was either pre-broken, or not really glass.
The mother-in-law is nowhere in sight when the gunshot is heard and the man allegedly killed himself. They have to go fetch her, sleeping in her room. Yet, when questioned, she admits having been with her son-in-law up until moments from his death. Yet, the cops (Gannon, Friday) don't think that it's odd, that a gunshot rang out while they were desperately trying to break into the living room. Yet, she admits to have been there, with him, and never once bothered herself to open the door for the cops, nor to talk to them. She simply, casually, went back to bed knowing there was a death in her house. She isn't so much as questioned about why.
The actress playing the wife, in the pink bathrobe, asks "is he still alive?" to Friday, as matter-of-factly as if she were asking "is he still sleeping?" and she isn't questioned about that.