No Man's Land (1988)

Young police officer Benjy Taylor (D.B. Sweeney) is assigned a case that has him working undercover to insinuate himself into the good graces of an auto-theft ring. To his surprise, he becomes friends with the head car thief, Ted Varrick (Charlie Sheen). Worse, he also falls for Ted's seductive sister, Ann (Lara Harris). Soon, Benjy begins to lose focus of the line that separates cop from crook, and starts stealing expensive automobiles alongside the criminals he was sent to monitor.