A man wanted over the murders of two people was arrested after he was spotted in the street by an off-duty police officer.
The officer, who was driving to work, recognised James Allen in Leeds and watched him for several minutes until his colleagues arrived to help.
Police chased 36-year-old Allen on foot before arresting him on Crown Point Road at around 7.20am on Sunday. He will now be questioned in West Yorkshire on suspicion of the murders of 81-year-old Colin Dunford, in Middlesbrough, and Julie Davison, 50, in Whitby.
Speaking at a news conference at Cleveland Police headquarters in Middlesbrough, temporary Detective Chief Superintendent Gordon Lang praised the officer for an "excellent piece of police work".
Mr Lang said: "I can confirm this morning that a 36-year-old man has been arrested on suspicion of the murders in both Middlesbrough and North Yorkshire.
"Just after seven o'clock this morning, in Leeds, an off-duty police officer saw a man. His suspicions were raised around this man, he took up observations, maintained observations, called for assistance. That assistance arrived and, after a short foot chase, that man was arrested."
Cleveland Police and North Yorkshire Police issued an urgent appeal to find Allen on Thursday following the murders. Mr Lang thanked members of the public for their "fantastic" response to the appeal and asked anyone with further information, particularly in connection to the route possibly taken by Allen from Middlesbrough to Leeds, to come forward.
The senior detective said he had no information to suggest other offences had been committed but he urged people to check on any neighbours, friends or family members they had not seen recently. He said: "Please check on people, friends, relatives, and let's make sure everybody's okay."
Cleveland Police launched a murder investigation after Mr Dunford was found dead at his terraced house in Leven Street, 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.
Ms Davison, 50, who lived alone, was found dead by her sister at her rented flat in Church Square, Whitby, on Wednesday. She had also suffered serious head injuries, police said.