The Night of the Cat (1973)

Beth tracks down the mobster responsible for her sister's death. Crime boss Mr. Demmons owns a topless bar and also runs a prostitution racket in which innocent girls are kidnapped, taken to a secret clinic, and given drugs. Hopelessly addicted, the girls pay for the drugs by becoming prostitutes. Beth's sister escaped and was on her way to tell authorities about the mobster's operation until his goons ran her down on a country road. Beth joins forces with a reporter and takes karate lessons as part of an elaborate revenge scheme.