The Big Black Pill (1981)

Joe Dancer, a private detective working in Los Angeles, is handed a big-money case by Tiffany Farinpour of the Farinpour family, which includes powerful politicians. Tiffany needs Joe to find her younger brother David, who has left the family under a cloud. In trying to find David, Joe is warned off by several thugs before he finally finds David in a small town, just trying to live a quiet life. But just seconds after he's located, he is killed by a hidden assassin, Joe discovers that all evidence of David's life in the town has been erased, and Joe faces a murder charge. With the clock ticking, Joe must find the killer in a plot that involves danger and deep family secrets.