Police have confirmed the man who walked out of North Sea Camp on Monday was a convicted rapist.
David Razzaque, 46, was last seen at the Freiston Shore open prison at about 4.45pm.
He was described as serving a life sentence for serious offences but officials have now admitted those were of a sexual nature.
It is thought that Razzaque could be at large in Derby where he committed his original offences.
Razzaque is of mixed white and Asian race, has a shaven head with a distinctive ponytail on the top of his head, and a beard. He has a tattoo of a dragon on his upper right arm.
Derby Detective Chief Insp Paul Tatlow said: “There is a strong possibility that he is sleeping rough somewhere in the city so we’d like people to contact us if they see anything suspicious around derelict or unused buildings.
“Also if anyone has seen Razzaque or knows where he is they should contact the police immediately on 999 and mention incident number 774/26 January. Given his previous convictions he should not be approached.”
If seen, the public are advised not to approach Razzaque, but to contact police straight away.