In this movie it was the young woman in the above trailer - 3 or 4 pipe bombs & 4 deaths - 5 including her father who died with a broken heart.

@FrayedBear I read the book back in the 90's, very disturbing. I could never bring myself to watch the film. I know what it is to discover a close family member is a monster, and to wonder how I never saw it.

@LenHazell53 Folies à deux? The drive to love frequently blinds reason. Once I intended about 10 CDs of performed poetry carrying the title "madness & cousins". Nearly all the poems to be love poetry. It never happened because performing, broadcasting & recording about 50 starting with old favourites like the Tom o' Bedlam series, Cocaine Lil, the Tattooed lady and Cuddle Doon and About 500 others identified that at least round here there is a lack of appreciation of what I do. I needed more & less interference in my life.
Most however do not associate being in love to be a form of madness or perhaps more correctly an inducement to madness.