Parents who took video and photos of their children playing in a park on Halloween may have caught a suspected killer on film, police have said.
Detectives investigating the murder of Rocky Djelal just before 2pm in Southwark Park, Rotherhithe, south-east London, on October 31 believe his attacker was waiting for him for at least 15 minutes before he struck.
The father-of-one was stabbed twice by a masked killer in what is believed to have been a targeted attack that lasted less than 30 seconds.
The murderer, who work dark clothes, work boots and a yellow high-visibility vest, was caught on CCTV walking calmly away from the scene near a children's playground and a school.
One week on appeal for information on the murder of 38-year-old Rocky Djelal in #Southwark Park – officers will be at the scene today between 13:00-15:00hrs and are appealing directly to the community to speak with them https://t.co/yOXn7UrWbMpic.twitter.com/NsRPLvJ8nX
— Metropolitan Police (@metpoliceuk) November 7, 2018
Appealing for witnesses a week after the murder, Detective Chief Inspector Simon Harding said: "The park itself was quite busy that day, it was the middle of the day and there were quite a few people around with either kids or jogging or walking dogs, and because it was quite a nice day people would have taken a lot of photographs or video of their kids.
"It was also Halloween, so people would remember being there."
He asked anyone who was in the park to think back about what they did from around midday in case they caught Mr Djelal or the suspected killer on film.
Investigators have been scouring CCTV to see if the 38-year-old was followed in the hours before his death.
He had convictions for violence and had only been released from prison in July, leading detectives to consider whether the murder was a revenge attack.
No one has come forward to say they planned to meet him in the park, meaning the killer might have lured him there.
Mr Harding said: "One of the biggest lines of inquiry that we have along with CCTV is to understand Rocky's past and those who might have and bear a grudge against him."
Mr Djelal was jailed for six years in 2014 after pleading guilty to conspiracy to cause GBH in the mistaken identity murder of City porter Christopher Foster.
Aytach Lisani, the knifeman who murdered Mr Foster in a revenge attack against the wrong man, was jailed for life with a minimum of 23 years at the Old Bailey.
In 2001, Mr Djelal was cleared of taking part in a brutal Christmas Eve attack on a Turkish asylum seeker which left him permanently brain damaged.
Mr Djelal's family said in a statement: "Thank you to all of the people who rushed to Rocky's aid in the park and made sure our boy was not alone in his final moments.
"We are absolutely grief-stricken. We have lost our boy, our son who we adored. A father who was idolised by his daughter, a brother who was loved dearly and an uncle, nephew and friend who was loved and respected.
"Anyone who really knew you knows you have a heart of gold and you'd do anything to help those you love."