Grotesque
USA 1987. Director: Joe Tornatore
Cast: Linda Blair, Donna Wilkes, Charles Dierkop, Tab Hunter

A gang of punkrockers robs and kills a family in their vacation home in the mountains, leaving Linda Blair escaping in her pajamas. Then some angry sheriff (Charles Dierkop, so good in Roots of Evil) comes around and investigates. Then uncle Tab Hunter (a long way from fame) arrives and gets pissed off and takes revenge on the punks with the help of his weird mutated son. Somewhere there's a treasure also.