A murder investigation has been launched into the disappearance of a father who vanished more than five years ago.
Robert Duff was last seen on January 12 2013, when he failed to arrive at a celebration for his daughter’s 18th birthday.
Despite a lengthy missing persons inquiry police now believe he was killed that night.
Murder investigation launched after new information emerges concerning missing man - Robert Duff, 41, has not been seen or heard from since 12 January 2013 https://t.co/uWBFZ2nXcH pic.twitter.com/kGWehnTHEX— Metropolitan Police (@metpoliceuk) May 15, 2018
Searches are being carried out in open spaces near where he was last seen, including in Waterlow Park, Highgate, north London, with police divers scouring ponds, and at a flat in nearby Bredgar Road.
Mr Duff’s mother Helen Duff said: “Robert’s disappearance has always been forefront in our minds, and although we have always suspected that he may have come to some harm, there has always been the hope that he would return to us one day.
“Since hearing that this is now a murder investigation, that hope has been taken away from us and as a family we are devastated.
“Our only wish now is that Robert is returned to us so we can grieve together.”
The breakthrough in the case came after a television appeal on ITV London Tonight in January, which led a new witness to come forward.
At the end of February the case was passed to Scotland Yard’s murder squad.
Detective Chief Inspector Luke Marks said that Mr Duff was involved in a fight with two men on the night he died.
Two people were arrested on suspicion of murder on Monday and released pending investigation.
Mr Marks said: “It has been over five years since Robert’s family have seen or heard from him. Every day they have had to carry on without knowing what happened to him.
“I am making an appeal to the public once again, to come forward and help us complete the missing pieces of the puzzle.
I urge anyone who saw or heard from Robert Duff on January 12 2013 to come forward and share what they knowDetective Chief Inspector Luke Marks
“I urge anyone who saw or heard from Robert Duff on January 12 2013 to come forward and share what they know; it may seem like nothing to you, but it might be the information we need.”
Mr Duff had been to the flat in Bredgar Road on the night he died, and several people were there.
His bank card and mobile phone remain missing.
Describing the 42-year-old as “a well-known and likeable character” in the local area, Mr Marks said there was no obvious motive for someone to cause him harm.
The fight on the night he died appears to have been “spontaneous”, he said.
Mr Duff was friends with a woman called Lana Purcell who is also believed to have been murdered, but police are not linking the two cases.
Anyone with information can call police on 020 8358 0200.
Mrs Duff, 65, and her granddaughter Stephanie said that on the day he disappeared they knew instantly that he had come to harm.
His mother said: “We knew that was out of character for him, especially for an occasion like that, his daughter’s 18th birthday, he would contact us. We knew straightaway something wasn’t right.”
Stephanie, 23, said the family had tried to “get the message out there” but it was difficult because “people go missing every day.”
It’s a horrible feeling knowing that he’s been murdered and he’s out there somewhere and we’ve got no control over thatStephanie, Robert Duff's granddaughter
She said they still cannot grieve because they do not know where the father-of-two’s body is.
“It’s a horrible feeling knowing that he’s been murdered and he’s out there somewhere and we’ve got no control over that.
“I hate that feeling knowing that he’s out there somewhere now, alone, after what happened to him. I always said I’d never give up and I’d find him, and I will.”
They believe that people know what happened to him and need to “do the decent thing” and come forward.
Mrs Duff said: “At least if we knew where he was then we could lay him to rest and we could start the grieving process.
“There’s been a wall of silence around this from the beginning when Robert went missing, and I think it’s about time now that people stop protecting people and come forward and do the right thing.”
Addressing her father’s killers Stephanie, who had her first baby six weeks ago, said: “They’re better off coming forward because we won’t ever stop until we find out and find my dad.
“After this time those people who did murder my dad must have thought it was forgotten about.
“So they need to remember you will get found out in the end. I want them to know that, they’re better off coming forward now.”