A medical student plunged to his death from a balcony while thought to be on legal highs, an inquest heard.
Tianhong Tang, 19, a student at St George's University of London (SGUL), was seen by passers-by swinging his legs over the balcony of his flat in Elite House, Broadwater Road, Tooting, on December 4.
The Royal Courts of Justice heard neighbours looked on in horror as the teenager appeared to lose his grip and plummet to the floor.
Witness Genene Carpene was collecting her children from school at about 3.30pm when she spotted Mr Tang swinging his leg over the railing of the Juliet balcony.
She said he swung his leg back inside, but remained sitting on the railing and turned to face his flat with a glazed expression.
But suddenly he lost his grip and fell backwards onto a concrete patio area, crashing to the floor with a loud bang.
Miss Carpene said: "It looked like he was in the moment, he was not looking at anything. I don't know if he was on drink or drugs.
"He was still on the railing itself, his bottom was on the actual railing. He was holding on then slipped, I suppose he could not hold any tighter."
Builders from a nearby site helped police officers get to the scene by cutting through a metal fence surrounding the patio.
Officers discovered Mr Tang surrounded in a pool of his own blood and performed CPR.
He was taken to St George's Hospital by the London Ambulance Service, but died on December 7 of a traumatic brain injury.
Police officers discovered empty packets of legal high salvia divinorum premium mazatec leaf inside his flat, cannabis traces and a bong.
A scrawled note left at the scene read "Just don't want to die", with the address of a Thomas Baker in LA on the back.
The message continued to read: "Wasted, this is too good for people on acid. Chemical weapon. What the f***."
But a toxicologist was unable to detect any alcohol or drugs in his blood, despite running a scan for cocaine and cannabis.
Coroner Dr Shirley Radcliffe recorded a verdict of accidental death, claiming the results make it impossible to conclude the effect of legal highs.
She said: "We still are slightly perturbed as to why he was reported to be glazed, whether is was the effect of a legal high or something else we are unlikely to know.
"I think the evidence we have got would suggest this was an accident, there is nothing to suggest this was a deliberate action.
"Unfortunately we don't know all of the answers to the questions which I am sure the family would wish to ascertain, which makes it more sad for the family."
- Hundreds of yards of new paving laid as repair work to Putney Bridge pushes on
- Prolific thief jailed for breaching ASBO after dawn visit to Mitcham
- Everyone happy as Nappy Valley named the friendliest place Wandsworth
- Television calling for Battersea admin worker
- Spanish film night returns to Battersea haunt