Evil Laugh (1986)

An old orphanage has just been rebuilt after it was mysteriously burned to the ground over a decade ago following accusations of child molestation and abuse by Martin, whose own father committed suicide out of shame. Needless to say he couldn't prove his innocence, suffered a psychotic breakdown which subsequently led to him systematically slaughter the other occupants, including the kids, particularly the accusers, before perishing in the blaze that followed. Now a group of med-students are brought in by a seemingly benevolent doctor turned pediatrician, Jerry who seeks to fix the place up as less an institution more of a foster home. One of the students is set on dwelling there at this current position, while the others are set on helping them settling in. But soon they'll discover that our current owner has been secretly disposed of by an intruder, who is still lurking close by. Jerry's (now ex) fiancée Connie, Barney (who said his farewell to Jerry moments before meeting his end) and their assorted mates, Mark, Johnny, Tina, and snobbish couple Sammy and Betty, may soon find themselves joining our dearly departed doctor sooner than they'd like, when our intrusive loony decides to make a return visit.