Under the Gun (1987)

Mike Braxton (Sam Jones) a St. Louis cop, receives an urgent call from his brother Tony (Nick Cassavetes), a small time thief in Los Angeles. The call ends abruptly and Mike rushes to LA to find his brother has been murdered. When questioning Tony's girlfriend, she's gunned down in front of him. Mike quickly learns Tony was a courier for Simon Stone (John Russell), a big time arms-smuggler. When Mike meets Stone's lawyer, Samantha Richardson (Vanessa Williams), the two team up to bring down Stone's arms smuggling empire. But Mike's infatuation with Samantha keeps putting them in greater danger.