A former prison officer has been found guilty of raping five women and attempting to rape a sixth.
Police said it would have been "only a matter of time" before Mark Scott, from Hull, killed someone.
The 34-year-old was convicted of nine counts of rape and one of attempted rape at Hull Crown Court.
Scott, who will be sentenced in June, raped five women and attempted to attack a sixth after meeting them on dating sites and nights out.
Det Sgt Anneliese Tomlinson, from Humberside Police, said the conviction was a "very significant result" as he was a "serious danger to women".
She said: "Because of the way he acted and the offences he committed, I feel it was only a matter of time before he killed someone.
"His use of force and aggression against these women verged on the perverted and the extreme.
"He would not stop to get what he wanted."
The attacks took place between 2005 and 2018.
The former HMP Hull officer had claimed the sexual activity was consensual during a seven-week trial.
But Det Sgt Tomlinson said: "He took his chances, forced himself on the women he was with and thought he could get away with it. But he hasn't."
She said the six women had shown "strength and courage" and should not be considered "victims".
"I want to say how much I admire them for their bravery and for stepping forward," Det Sgt Tomlinson added.
Scott, of Daville Close, was acquitted of two further counts of rape against one of the women.