Charmed (1998)

S1E20 The Power of Two

Once Piper heads out for a business trip, tension quickly arises between Prue and Phoebe. They manage to put their disagreements on hold when they encounter the ghost of a serial killer seeking vengeance against those who condemned him to death. At the same time, Andy finds himself under scrutiny as Internal Affairs starts to pay attention to the numerous unsolved cases he's been dealing with.