The victim is believed to have been between 14 and 25

A post-mortem examination showed he had been battered around the head with a weapon before being doused in petrol and set alight.

A Scotland Yard spokesman said the three men questioned in connection with the incident were all Asian, and aged 21, 19 and 17 years.

They were arrested together in a car in Wembley, north west London, at 1800 GMT on Friday.

They were released on bail on Sunday to return to a north London police station later in March, pending further inquires.

Police are still trying to identify the dead man.

The detective leading the inquiry said forensic analysis had revealed several distinguishing features about the man's teeth.

Teeth

Detective Superintendent Nigel Mawer said: "The teeth are in very good condition, he doesn't appear to have had dental treatment, but unfortunately that makes him very difficult to trace through dental records.

"He has a congenital abnormality that may be common to siblings and close family.

"He has two lower molars missing and doesn't have any wisdom teeth.

"This doesn't look like an abnormality but members of the public, who visit the dentist regularly, would know if they are missing two lower molars and they would certainly know if they didn't have any wisdom teeth."