The News of the World claimed a Fleet Street record when it offered a reward of £250,000 to catch the "Suffolk Strangler".
Managing editor Stuart Kuttner said the reward is "as far as I am aware, unprecedented".
He added: "A lot of thought went into this, and the News of the World liaised closely with Suffolk Constabulary.
"The News of the World has a long history of supporting police investigations and we take a view that here is an unprecedented series of shocking crimes.
"We decided that the role we can play — after close consultation with the police — is to offer a very significant reward to see if this will tease out some vital piece of information."
Detective chief superintendent Stewart Gull, from Suffolk Police, said: "I am grateful for the support from the News of the World. Any offer that leads to the identification of whoever is responsible for these crimes is welcome."