Endangered Species (2002) on Netflix

Plot summary

Victims are attacked in gyms and spas, and the police have a serial killer theory but no suspect. Lieutenant Mike Sullivan works the case with Wyznowski and Yamata. At one scene a young woman survived by hiding in a locker; she is in the hospital under heavy medication. Sullivan sees a stranger at the scene, then finds the same man questioning the survivor, who took him for a police officer. Sullivan and Wyznowski give chase, and Sullivan brings the man down with a taser. At the station the man refuses to answer questions and the police cannot hold him. A new attack at a strip club leaves many dead.