Detectives believe the tablet the dead teenager took is “a red hexagonal pill named Red Bull” and are concerned that others may have taken it.
Detective Superintendent Pete Hill said: “Our thoughts are with the family of the teenager, and specialist officers are supporting them.
“We believe the tablet taken is a red hexagonal pill named Red Bull, which is believed to be MDMA, and we are concerned there may be others who have also taken this. While the cause of death has not been confirmed, we would advise anyone who has taken it to seek medical advice.
“We would also ask anyone who purchased any pills but have not yet taken them to please safely dispose of them.
“If others were at the same event last night and are aware their friends took this drug, please check in on them to ensure they are OK.”
Tests on Red Bull pills have previously found some containing N-Ethylpentylone.
According to dancesafe.org, a group that tests recreational drugs for their purity, N-Ethylpentylone produces some of the same effects as MDMA, but is “significantly stronger and substantially riskier”.