Clare Smith, Samuel Guidera's girlfriend, told ITV News that she often thought about him lying in the street, in the moments after he was stabbed.
She is urging anyone who knows his killers to come forward:
" The people responsible have been able to move on with their lives get jobs, get married and have children but for Sam's family and friends life has stood still.
"I constantly think about him lying on the street alone without anyone to comfort him and ask his killers or anyone who knows who they are to put themselves in my place."
Officers will be at the scene of the attack near Penge East Station tonight handing out leaflets as part of the renewed appeal for information.
More top news
Arsenal managed to beat Everton at the weekend but it wasn't enough to finish in the top for the first time in Wenger's time at the club.
The entertainer was held for the murder of Stuart Lubbock, who was found dead in his swimming pool in 2001, but never charged.
Although the diamond was believed to be cut in the 19th Century, its history and how it arrived at the car boot sale is unknown.