Mission Kill (1985)

J.F. Cooper is an American demolition expert when he visits his best friend Harry whom is smuggling arms to a fictitious Latin American country to the country's rebels, and Harry invites Cooper to tag along with him. When Harry is murdered by foreign mercenaries, led by a brutal assassin-for-hire named Kennedy, Cooper seeks his revenge by murdering Kennedy, assuming his identity, and after reclaiming the stolen arms, assumes Kennedy's name and identity, and joins the rebel freedom fighters in their war against the oppressive totalitarian government.