Police discovered clothes and shoes neatly placed at the spot where a Bradford teenager fell 30 feet to his death.
Christopher Luke Stoton was found dead on a small triangle of land near Bradford Interchange and the NCP car park on Saturday.
The 18-year-old, of Reyner House, Manchester Road, Bradford, was wearing only a shirt and boxer shorts.
Police discovered the rest of his clothes, folded neatly in a pile, near the place from where he is believed to have fallen.
Detectives say the circumstances surrounding his death and how he came to be half-dressed remain a mystery.
A post-mortem showed he suffered multiple injuries - particularly to his head - consistent with a fall from a great height.
The man heading the investigation, Detective Chief Superintendent Max Mclean, said Mr Stoton was last seen at about 4am on Saturday in the Manchester Road area.
He was wearing a cream fleece top, blue jeans and dark shoes with a crocodile motif on the side.
When his body was found by car park staff at 7.30am on Saturday, he was wearing only red boxer shorts and a light blue long-sleeved striped Ralph Lauren shirt.
Det Ch Supt Mclean said: "His parents are extremely distraught and the mystery surrounding this incident makes it all the more worse for them.
"We still don't know why he stripped off. The latest information we have is that he had been drinking throughout the day and evening.
"He almost certainly fell to his death from the Interchange concourse, as that is where his clothes were found.
"I am very keen to hear from anyone who saw him between 4am and 7.30am on Saturday in the Manchester Road or city-centre areas."
It is still not known exactly how long the teenager's body had been there. Detectives say there appears to be no evidence of an attack.
Mr Stoton was unemployed and single. A female flatmate was today too upset to talk about his death.
Anyone with information, or who saw Mr Stoton early on Saturday, should contact Bradford Central CID on (01274) 376485.
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