A man wanted over the murders of two people was arrested today 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.
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."
He added: "I have to say what an excellent piece of police work by an off-duty police officer."
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.
"Please check on people, friends, relatives, and let's make sure everybody's okay," he said.
Mr Lang said a mountain bike used by Allen at the beginning of the week had been found on Thursday in Scarborough and they did not know how he had travelled to Leeds.
He said he wanted to find out details such as where Allen had been during the week and who he had seen.
"It's important we fill in those gaps," he said.
"We continue to appeal for sightings on what has been a journey. A journey that started on Monday April 23 in Middlesbrough; on Tuesday and Wednesday last week, Whitby and Scarborough; Thursday and Friday in Leeds; culminating in this morning's arrest.
"We are still looking for sightings and information, particularly over the last couple of days in the Leeds area."
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.
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 in Church Square, Whitby, 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 West Yorkshire Police became the third force to join the hunt for Allen, with more than 100 detectives working on the case, after sightings of the suspect were reported in Leeds on Friday.
Yesterday, police also released CCTV images taken of Allen in Scarborough during the week.
The pictures showed Allen in a cash exchange in the seaside town on Tuesday and Wednesday and in a sports shop on Wednesday.
Mr Lang said the images released and the appeals to the public helped to find Allen.
"It comes as no surprise to me that someone has done the right thing," he said.
Anyone with information is asked to contact Cleveland Police on the non-emergency number 101.