Samuel Guidera murder: Police video posted on YouTube
Video footage of the night a student was murdered in south-east London has been posted on YouTube by detectives.
The video shows CCTV of all the people who were in the area when Samuel Guidera, 24, was attacked near Penge East station, Sydenham, in February.
Officers want to identify up to 32 people who can be seen in the footage.
Mr Guidera was found collapsed at a bus stop having been stabbed shortly after getting off a train. It is thought he was the victim of a robbery.
The University of Greenwich student was found at 2154 GMT, 200 metres from the railway station.
He had just arrived on the 2117 train from Bickley having spent the day watching football on TV with friends.
At first, several members of the public went to help him believing he had been hit by a car as he lay in the road.
Det Ch Insp Laurence Smith said: "If you believe you may have been in the area that night in February we urge you to watch the video, come forward and let us know who you are.
"We are trying to piece together what happened to Samuel and you may hold important information that could help our investigation."
Two men, aged 39 and 18, arrested on suspicion of murder, have been bailed until April. A third man, aged 28, arrested over the inquiry has also been bailed until next month.