Maybe a lone killer could be operating in a psychotic fugue.

Mass killers like Mr. Cho operate on their own, and are likely to want to end the world, their own and others'.

Reports were released publicly of the possibility a serial killer was operating in the Oakland County area.

The worry is, this killer apparently operates the same nights you're on duty.

If these two killers were actually one mind-linked creature-a Paratwa-our tests would have uncovered certain characteristics relating to the way the killers operated.

I want to see how killers operate.

The killer has been operating in the north for over a year now, and there has been much criticism of the police's handling of the investigation.

His bloodlust shatters all the conventional wisdom surrounding the motives and mechanics of how serial killers operate.

On the other hand, she already felt the faint stirrings of an idea of how this killer operated and where the police might start their search for him.

How and with what diabolical cleverness the killer had operated... but proof... that was another thing.