Richard Osborn-Brooks, 78, was arrested on suspicion of murder over the death of Henry Vincent but was later told he will face no further action.
Billy Jeeves, 28, is being sought by police following the break-in that took place in Hither Green, southeast London, on 4 April.
It is not thought that Jeeves is responsible for the death of his alleged accomplice.
The suspect is said to have links to Orpington and Swanley in Kent and Cambridge.
The Metropolitan Police also want to hear from people who might have seen his white Vauxhall Astra van, with the registration GU52 AXT, in the days before or after the burglary.
The vehicle was found burnt out and destroyed in Star Lane in Orpington on Saturday 7 April.
His alleged accomplice Vincent died after the break-in at Mr Osborn-Brook’s property.
Detective Chief Inspector Simon Harding said at the time: “This is a tragic case for all of those involved.
“As expected with any incident where someone has lost their life, my officers carried out a thorough investigation into the circumstances of the death.”
Mr Osborn-Brooks’ arrest sparked outcry from his neighbours.
An online fundraising campaign to pay for his legal fees or to “make his home more secure” raised £7,609 in four days.
Vincent has emerged as a career criminal who was wanted by Kent Police in connection with a distraction burglary at a pensioner’s home in Farningham in November 2017.
He was also on the force’s “most wanted” list in 2013 over a burglary in Gravesend, Kent, according to reports.
Police said one of the suspects who entered Mr Osborn-Brooks’ home was armed with a screwdriver and forced his way into the kitchen, while the other man went upstairs.
It is thought that a struggle took place between the pensioner and Vincent who was stabbed in the upper body.
Police have not said what object was used to inflict the fatal blow.
Both intruders are said to have fled after the altercation at the home in South Park Crescent, but Vincent collapsed on nearby Further Green Road.
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An eyewitness is said to have seen a man attempt to drag Vincent towards a van but eventually left the area without him.
Vincent was taken by ambulance to a central London hospital where he later died.