One man has been arrested and charged with trafficking and possessing drugs.
Police suspect a toxic batch of MDMA is to blame for the death of a 30-year-old man and 20 more hospitalisations in Melbourne this past weekend.
As ABC reports, it is believed those recovering in hospital ingested illicit drugs at nightclubs in South Yarra's Chapel Street precinct.
"One person is in a stable condition, all of the others did require different levels of hospitalisation, and there's also an investigation into a fatality that occurred on the Saturday morning in relation to a drug overdose," Detective Senior Sergeant David Newman said.
Newman added that there are fears the bad batch has also been distributed outside Chapel Street.
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"Obviously things have centred around that Chapel Street entertainment precinct area, but that's not going to preclude it from being around the CBD," he said.
"As we know this sort of drug, when we get a batch like this it comes through the tentacles of the drug dealing world [and] they aren't going to be confined to one area, they're going to spread out and we don't really know where it's going to become evident next."
ABC has reported that a 30-year-old man was arrested yesterday morning and charged with trafficking and possessing MDMA.
He is to appear at the Melbourne Magistrates Court today.