No Mutants Allowed

who went around putting blades on the animals?

A disgraced professor from a local college who was squatting in the basement of an abandoned slaughterhouse, a local gang lets him hang out there because it keeps people from snooping around the surrounding buildings where they have all kinds of shady criminal activity happening.

The gang (which is subservient to a larger more sophisticated mafia-style group) stole something he needed for an experiment and gave it to him as a gift, casually framing the players in the process. The players basically had to solve the theft themselves to clear their name.