A teenage rugby player died after taking a banned fat-burning diet pill.
Chris Mapletoft, 18, swallowed DNP, a chemical sold online which is being used as a dangerous quick-fix slimming aid.
He died at home in Twickenham on June 18.
At the time, it was believed he may have died from meningitis, but an inquest last week was told the cause of death was the chemical, known as 2,4-dinitrophenol (DNP). The coroner recorded a verdict of accidental death.
Police are trying to find out where he bought the pills and whether he was warned of the risks of DNP. Although banned for human consumption, the toxic substance itself is not illegal because it is used as a chemical pesticide.
Those who have overdosed on DNP have likened it to 'cooking from the inside', because it can cause the body to overheat.
A police spokesman said: "Dinitrophenol has no legitimate use as a medicine or food supplement, and is not safe for human consumption in any form.
"It is a poison which interferes with the normal way the body gets energy from fat. This can lead, as in this case, to death from overheating."
Chris had just completed his A-levels at Hampton School, West London, and was also a star of his school's first XV rugby team, winning a player of the tournament trophy last year.
His headteacher Kevin Knibbs said: "He was a sportsman but he was also a very serious academic too. Most importantly of all, he was a fantastic guy, much loved and greatly respected here by all of us."
DNP, which is popular with bodybuilders, has been linked to 62 deaths worldwide and has caused three in Britain in the past year. It was originally launched as a slimming aid in the 1930s but was banned shortly afterwards due to its side-effects. Last month the Food Standards Agency issued a warning over the availability of the chemical as a 'fat-burning substance'.