Bad Influence (1990) / Masquerade (1988)

Bad Influence (1990): Michael, a wimpy young executive, is about to get pulverized by a jealous boyfriend in a bar when a handsome, mysterious stranger steps in--and then disappears. Later that night, while jogging, Michael runs into the stranger on a pier. He introduces himself as Alex, and the two go out to an underground club. Within a matter of days, Alex wheedles his way into Michael's life and turns it upside down, and Michael doesn't realize that Alex is a dangerous sociopath until it's too late

Masquerade (1988): A recently orphaned millionairess, Olivia, really hates her scheming step-father. Olivia finds love with a young yacht racing captain, Tim, who isn't completely truthful with her. When the two run into a problem the local cop, who happens to be an old friend of Olivia's, seems to be turning a blind eye to incriminating evidence.