Brighton police this afternoon named the victim of the Elm Grove murder as 51-year-old Gordon Stalker.
Mr Stalker, a regular at the Lewes Road Community Garden project, was stabbed to death at his home of 16 years by someone police believe he knew.
Today tributes to him were posted on social media sites by friends still coming to terms with his death.
And a memorial to him will be held at the Lewes Road Community Garden this Sunday from 2pm to 4pm.
Guerrilla gardener Richard Reynolds posted this picture of him on Twitter, describing him as: “The great late guerrilla Gordon . . . at the Lewes Road garden last year”
Duncan Blinkhorn of the Lewes Road Community Garden Project said on Facebook: “Many of you will have known the lovely Gordon who did so much to make the garden a welcoming and vibrant space and helped so many people.
“Many of us who are involved in the Garden are in a state of shock at this tragic and senseless loss.”
Detective Chief Inspector Trevor Bowles, of the Sussex Police Major Crime Branch, said: “We still urgently need to trace the murder weapon. I believe that a knife has been used to commit this murder.
“Should anyone find a blood stained knife, please call us. It is vital that we trace this weapon.
“Specialist police search officers have been searching the area for a weapon and today drains are also being checked.
“We have spoken to some witnesses who are helping to put together exactly what happened and why.
“But I still urge anyone who saw a confrontation on the doorstep of 67 Elm Grove, at about 10am on Monday morning, to come forward and help us find the killer.
“It is quite likely that the confrontation was visible to passers by who may not have realised its seriousness.
“The house is a third of the way up Elm Grove on the left hand side.
“From all the circumstances I believe this was a targeted attack and that the victim would have known his killer.”
Anyone with information is asked to contact Sussex Police on 0845 6070999 or the independent charity Crimestoppers anonymously on 0800 555111.