Ipswich teenager Adrian Lubecki has admitted supplying a deadly batch of "Superman ecstasy" that is thought to have killed three Suffolk men.
Lubecki, 19, pleaded guilty to to one count of supplying PMMA, a similar substance to ecstasy that takes longer to kick in, and one of possessing amphetamines with intent to supply at Ipswich Crown Court.
The batch is being linked to the deaths of 23-year-olds Justas Ropas and Gediminas Kulokas as well as that of a third man in Rendlesham, Suffolk.
Suffolk Police offered a drug amnesty in the wake of the deaths in the hope of removing the drug from the streets.
Officers then found more than 400 of the lethal pills, which feature the Superman logo, stashed next to Norwich Road, near Ipswich town centre, on the evening of Sunday 4 January.
Lubecki will be sentenced in the week beginning 16 February.