Bad Influence
(1990)

After Michael (James Spader) kicks out his "evil friend" Alex (Rob Lowe), Alex kills Claire (Lisa Zane) and manipulates the evidence so that it looks like Michael did it. Michael and his brother Pismo (Christian Clemenson) get rid of the body in the La Brea tar pits.

Alex tries to kill Michael by sabotaging his car, but fails.

Michael lures Alex to a dead-end street, where he points a gun at Alex. In a dialogue, Alex confesses all what he did, while Pismo films without Alex knowing. After the "confession", Michael points to the camera, and Alex tries to assault Michael. Michael shoots him. Pismo calls the police, and Michael plans to tell them all what happened.

(Note "desperate housewives" Marcia Cross in a small role as the blonde girlfriend of Alex)

Thanks, Tilman!