A man being sought after a sex attack on a teenager is a serial rapist who has spent 10 years in jail.
Richard Ewing has been described by police as "extremely dangerous"
Richard Ewing has been described as "extremely dangerous" and people have been advised not to approach him.
Detectives want to question Mr Ewing, originally from Devon, over an attack on a 17-year-old girl in fields near Weymouth in Dorset, on Saturday.
At least 100 officers are now involved in the search for the 41-year-old, police said.
A Home Office spokeswoman has confirmed that Mr Ewing had been residing in "approved" accommodation in Westway Road, Weymouth.
She said: "We can confirm that Richard Ewing was released from prison on his mandatory non-parole date in December 2005 after having received an 18-year sentence in 1995 for rape."
He was convicted at Exeter Crown Court of the rape of a mother of three in 1989, an attack on a woman, 46, in 1993 and raping a 32-year-old woman as she walked her dog along the River Exe in Devon in the same year.
He was caught when he attacked a student who fought back.
Mr Ewing has two distinctive tattoos, an anchor on his left thumb and a cross on his left forearm. He also has dots on the knuckles of his left hand and is 5ft 10in with a muscular build.
Police believe he also rides a yellow mountain bike and may be armed.
Officers have searched the coastal path in Dorset from Bowleaze Cove to Ringstead Bay and Chesil Beach.
Det Ch Insp Neil Redstone said: "Mr Ewing is extremely dangerous and should not be approached by the public.
"I would appeal to Mr Ewing, or anyone who knows him and his whereabouts, to please contact Dorset Police as a matter of urgency.
"All calls will be treated in the strictest confidence. Mr Ewing's description has been circulated to police forces nationwide."