“The drugs are believed to have been brought in and also bought at the event,” Hussein said at a press conference here today.

Yesterday, he had said the four who died were believed to have consumed ecstasy, although investigators were still waiting for the toxicology analysis report for confirmation.

Hussein told reporters today the victims were not related to each other.

He said police would summon the event organiser, and the first aid team stationed at the event, to give their statements.

He did not give further details.

As of yesterday, police have recorded statements from six witnesses. They plan to question others, including the victims’ friends.

While they were investigating the case as sudden death, police said they were also investigating the possibility that the victims could have been poisoned.

Police continue probe into teen’s death

Hussein said police are still waiting for the toxicology and post-mortem reports to determine the cause of death of 15-year-old Yap Xin Yuan.

Xin Yuan’s decomposed body was discovered in Banting, Selangor, on Monday.

He said police were investigating if her 16-year-old boyfriend, or his family members were involved in her death.

Xin Yuan was reported missing on Dec 19 after attending a lion dance practice at a basketball court at Batu 11 Cheras.

She is believed to have been murdered and her body thrown into a river.

On Tuesday, Hussein said her boyfriend was among three people arrested to assist in the investigation.