serial killer
serial murderer

The man is a serial killer at the front end of his career.

She played a person thought to be a serial killer.

He might be a serial killer, for all I knew.

"Maybe I should help you tell your sister and her friends about the serial killer."

The last serial killer had killed six kids before he was caught.

Maybe he couldn't let go until they caught the serial killer.

Now she must bring a serial killer to justice on her own.

The city had a serial killer, and they were all over it.

It looked like we had a serial killer on our hands.

What would their lives be like if they grew up as the children of a serial killer?