Police investigating the fatal stabbing of Dan Young made a second arrest last night.
A 35-year-old man was arrested on suspicion of murder on Thursday January 21. He remains in custody at a south London police station.
A 26-year-old man, who was orginally arrested on Tuesday morning on suspicion of wasting police time and then arrested on suspicion of murder, has now been bailed.
Police also withheld exactly how Mr Young died.
A postmortem examination revealed he died of a stab wound but detectives said they were not revealing where on his body he was stabbed.
In a statement, police said they were keeping an opening mind about whether Mr Young was attacked by a stranger or someone who was known to him.
Mr Young was killed in what is believed to be an unprovoked attack at about 8am on Tuesday, January 19, walking through Kendor Gardens, in Kenley Road, Morden, on his way to his second day at work.
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Police are also investigating an stabbing which took place 45 minutes before the murder of Mr Young in Lewis Road, Mitcham, when a 23-year-old was stabbed in the buttocks.
In a statement, police said: "The two incidents have not been linked forensically or evidentially, but due to the time and close proximity to Daniel's murder, the Homicide and Major Crime Command (HMCC) are working to establish if there is any evidence that the same suspect has committed both attacks."
Detective Superintendent Paul Monk of the HMCC said: "I understand the concerns of the public and particularly the residents of Merton, that the attack on Daniel Young was unprovoked and potentially committed by a stranger in a random attack.
"We too share those concerns and have allocated significant resources to find the person who did this.
"I reiterate that random attacks of this nature are thankfully rare in London, however we keep an open mind and at this early stage are not ruling out any line of enquiry."
Anyone with any information is asked to contact the incident room on 020 8721 4961 or Crimestoppers anonymously on 0800 555 111.
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