Sweet Justice (1991)

City councilor Susan takes bribes from Reevers and allows him to deposit his garbage illegally in an old mine. But when she learns that he also dumps toxic wastes which threaten the nearby water purification unit, she wants to cancel their agreement. She asks her ex-husband Steve, a cop, for help, but before he can do anything she's found dead. Her sister Sunny decides to take revenge with help of a couple of friends, who once formed a female martial fighting squad.