Police are linking a "degrading sexual assault" on an 87-year-old County Durham woman with another in the same town seven months ago.
Police say in the latest incident in Seaham, near Sunderland, the woman was woken at 0500 BST on Wednesday to find a man with a knife towering over her bed.
The man then carried out what detectives have described as a "prolonged and degrading" sexual assault as the defenceless widow lay in bed.
The woman, who is not being identified, needed medical treatment and is to be questioned by specialist officers from Durham Police soon.
Police are linking the incident to a similar sex attack carried out in the town in January.
During that incident, a man broke into the home of a woman in her late 70s and carried out a similar assault.
The latest attack scene has been sealed off, while forensic experts carry out a detailed search of the woman's home.
Extensive door to door inquiries are also being carried out.
It is thought the intruder broke in through a window.
Detective Chief Inspector Brian Tait, of Durham Police, described the attacker as "depraved".
He said: "The victim has been deeply shocked by what has happened and has received medical attention.
"Whoever has done this must be depraved.
"The people of Seaham should be reassured that we are doing everything we can to track down this man."
Mr Tait said the attacker was carrying a wooden-handled knife with a five-inch curved blade.