“This has all the hallmarks of an unprovoked and unsuspected attack.”

That is the view of detective chief inspector Cliff Lyons, leading the Morden murder investigation.

Detective Chief Inspector Lyons said they were looking into whether the stabbing in Lewis Road, Mitcham half an hour before the murder was linked.

Update: Residents shocked as 23 year-old stabbed in the buttocks in Mitcham recovering in hospital

"We are investigating the possibility of them being linked,” he said.

"We have to be open-minded. What if the arrested man is innocent? This has all the hallmarks of being an unprovoked and unsuspected attack."

A 23-year-old man is recovering from stab wounds to the buttocks after the stabbing in Lewis Road, Mitcham, at about 7.25am.

Detective Superintendent Paul Monk from the Homicide and Major Crime Command unit, said: “We are not linking them officially. We are investigating both simultaneously.

"They could be separate coincidences or they could be by the same attacker.

"We are speaking to an individual about that attack and other matters. We arrested him on suspicion of wasting police time."

Police said Daniel Young, 30, had been minding his own business walking to the second day of his new job through Kendor Gardens when he was stabbed.

DS Monk implied they had not found the murder weapon and the park was still being searched by forensic teams.

He said: “It appears that he was stabbed. I can’t presume it was a knife – the park is being searched.

"We are looking for the weapon that may have been used in the attack.

"We have found a number of things in the area but we can’t say what we have found at this stage.”

In terms of a motive, the murder squad are looking at two possibilities – that Mr Young knew his attacker, and that it was a stranger.

They are looking into how Daniel lived his life, his background, his friends and family to see if there are any clues.

DS Monk confirmed a number of members of the public found Daniel and tries to save his life before paramedics arrived.

“It is true there were a number of members of the public that found him and tried to save his life before paramedics got there. That’s absolutely true.”

A post-mortem examination is scheduled to take place today at St George's Hospital.

Police would like anyone who was in or around Kendor Gardens between 7.50am and 8.15am who has any information about the attack or the suspect to contact the incident room on 0208 721 4961 or Crimestoppers anonymously on 0800 555 111.