The brother of a man who died after being viciously attacked at Doncaster shopping centre is now a person of interest, with homicide detectives treating him as the man shown in CCTV at the scene of the crime.
Detective Inspector Mick Hughes said on Wednesday investigators received a significant amount of information overnight that led them to believe David Dick's older brother Jonathan Dick was the man captured on security footage in the lift lobby at Westfield Doncaster.
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CCTV: man wanted over fatal attack in Doncaster
Police say they believe the suspect is the brother of victim David Dick, who died after being attacked at the Doncaster shopping centre last Friday.
Not even his own family, who gave a heart-wrenching plea for help to solve the crime on Tuesday, recognised the man in the vision as Jonathan.
"You saw Carol [David and Jonathan's mother], John [their uncle] and Simon [their younger brother' in here yesterday," Detective Inspector Hughes said.
![Police would like to speak with Jonathan Dick, pictured, about the brutal death of his brother, David.](/web/20170208015248im_/http://www.theage.com.au/content/dam/images/g/u/7/x/q/y/image.related.articleLeadwide.620x349.gu7xtp.png/1486518150580.jpg)
"They were so traumatised yesterday and of course, that's been compounded by the news that we're looking at him [Jonathan]Â as a person of interest.
"Not one of them had an inkling that this was a possibility and even when we spoke to Carol this morning, she's coming to terms with it, but I really don't believe she has any belief that it is.
"These are a really honest, open family."
David was viciously assaulted, possibly with a sword, in a surprise attack as he stepped out of a lift in the Westfield Doncaster car park about 6am last Friday.
![David Dick's mother Carol Cloke, and his youngest brother Simon Dick, appealed for the public's help on Tuesday.](/web/20170208015248im_/http://www.theage.com.au/content/dam/images/g/u/7/c/t/5/image.related.articleLeadwide.620x349.gu7xtp.png/1486518150580.jpg)
He was found bleeding to death in the lift lobby minutes later by members of a gym group, who tried to save him.
Jonathan, 39, was last seen by another uncle on February 6. Police have been unable to locate Jonathan in his home at Seymour, and believe he may have gone to NSW or Queensland.
![CCTV vision of a wanted man taken from the day before David Dick was killed.](/web/20170208015248im_/http://www.theage.com.au/content/dam/images/g/u/7/8/0/u/image.related.articleLeadNarrow.300x0.gu7xtp.png/1486518150580.jpg)
The Dick boys' father, who died about six months ago, lived in Queensland and Detective Inspector Hughes said Jonathan would spontaneously drive up to see his father.
Jonathan, who has no criminal history, was recently diagnosed with a mental health condition.
![David Dick died after being viciously assaulted last Friday morning.](/web/20170208015248im_/http://www.theage.com.au/content/dam/images/g/u/7/8/0/y/image.related.articleLeadNarrow.300x0.gu7xtp.png/1486518150580.jpg)
"This may be an overwhelming situation to him. We're saying [to him] don't do anything to hurt yourself, you reach out to us," Detective Inspector Hughes said.
"Just remember, you've still got a family here regardless of the circumstances you may find yourself in."
![Jonathan Dick may be driving in one of these cars, possibly interstate.](/web/20170208015248im_/http://www.theage.com.au/content/dam/images/g/u/7/x/r/2/image.related.articleLeadNarrow.300x0.gu7xtp.png/1486518150580.jpg)
Jonathan, who recently cut his hair shorter, may be driving one of two cars: a 1997 blue Ford Fairmont sedan registration ONV 954; or a white 2002 Ford Falcon station wagon registration RIL 435.
Images of Jonathan and the vehicles have been released in the hope someone may recognise him or have information on his current whereabouts.
Detective Inspector Hughes said police had a number of suspects initially, including one on the Gold Coast who was ruled out immediately after he provided an alibi.
David, a former Melbourne High student and president and captain of the Glen Iris Cricket Club, was attacked as he walked to the bus stop to travel into town for his work as a concreter.
Police said his normal routine was to walk from his home in Doncaster and cut through the car park to catch the bus.
His attacker knew his routine and had been watching him, captured on CCTVÂ in the same location, at the same time, the day before he was killed.
Detectives believe he was planning to kill David last Thursday, but for an unknown reason, backed out and returned on Friday.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or make a confidential report at www.crimestoppersvic.com.au