A British girl (10) who died after swallowing what is believed to have been Ecstasy, may have taken up to five tablets of the drug.
If toxicology tests reveal that Jade Slack took Ecstasy, she will be the youngest victim of the dance drug in the UK.
An expert on the Class A substance said if a youngster took five pills, its effects would be up to 10 times stronger than a similar dose would have on an adult.
Detectives are continuing to question two women and a man - aged between 18 and 20 - about the circumstances surrounding Jade's death.
The youngster was taken ill while with a friend, also aged 10, at a house near her home in Galgate, Lancaster, Lancashire.
Police believe the occupants of the house were known to Jade's friend.
Professor Chris Milroy, a forensic pathologist at the University of Sheffield, said: "Clubbers who take Ecstasy tend not to take five tablets at once. If a 10-year-old girl took five tablets then, due to her weight, its effect would be five to 10 times more than a similar dose would have on an adult clubber."
Prof Milroy said if the toxicology tests reveal the tablets were Ecstasy then Jade would probably have died from either over-heating or heart complications.
PA