The Three Bad Wolves Grimm : Season 1 Episode 6

Blutbad Hap Lasser coincidentally survives a cunning arson attack which makes his home explode, two months after his brother died in a similar fire. Monroe reluctantly takes him in, also as a favor to Hap's sister, Monroe's own ex-lover Angelina. She returns to revenge both brothers and hates Grimms but resumes nocturnal hunt fun with Monroe. Lieutenant Peter Orson didn't call either case arson, but lost his own brother in a fire which may be a Blutbad's doing.