James Allen, who is suspected of killing two people in their own homes, was arrested today.
James Allen was arrested in south Leeds at 7.20am and is being held on suspicion of murder in connection with the deaths of Colin Dunford, in Middlesbrough, and Julie Davison, in Whitby.
It is believed that Allen was arrested on his 36th birthday.
A West Yorkshire Police spokesman said Allen was arrested on Crown Point Road after an off-duty officer saw a man fitting his description.
A murder investigation was launched after the death of 81-year-old Mr Dunford, who was found dead at his terraced house in Middlesbrough on Monday.
A post-mortem examination on Mr Dunford, who was last seen alive at around 5pm last Sunday, showed he had suffered serious head injuries as a result of a significant assault. Detectives said there was no sign of forced entry at the house.
Ms Davison, 50, who lived alone, was found dead by her sister at her rented flat on Wednesday. She had also suffered serious head injuries, police said.
Allen, who is originally from Blackpool, is believed to have known Mr Dunford when he lived next door to him in Leven Street about a year ago but it is not thought Allen knew Ms Davison.
Police linked the two deaths on Thursday and three forces joined the hunt for Allen, with more than 100 detectives working on the case.
Yesterday, detectives released CCTV images of Allen in Scarborough on Wednesday and in Leeds on Friday afternoon.