A "sadistic killer" refers to a person who takes pleasure in causing extreme pain and suffering to others, usually resulting in their death. Full definition
Dream House (PG - 13 for violence, terror, sexuality and brief profanity) Psychological thriller about a married couple (Daniel Craig and Rachel Weisz) whose relocation from NYC to a quaint New England town leaves their family the target of the same sadistic killer who had brutally murdered the previous owners of their new home. (kamwilliams.com)
To wit, a family of campers in a remote area randomly runs into a clan of sadistic killers and violence ensues. (dreadcentral.com)
That's the dilemma Detective Constable Maeve Kerrigan is faced with when she begins hunting down the elusive and sadistic killer stalking the streets of London. (bookpage.com)