Two Days in the Valley
(1996)

James Spader, tries to kill Danny Aiello, setting him up for the murder of Peter Horton, but doesn't succeed.  He DOES eventually kill his girlfriend (Charlize Theron), because she is injured and he figures she can't run with him.  

At the end, Spader is trying to kill Danny Aiello and Eric Stolz, but is killed by the suicidal man (Paul Mazursky - shown earlier at his wife's grave), who winds up with the nurse (Marsha Mason).  Danny Aiello ends up with Glenne Headley.  

Of the two cops, Jeff Daniels gets fired from the police force because of 'mental problems'; Eric Stolz gets shot.

Thanks JoAnne M!