A 19 year old man has died and three others are in hospital after it is suspected they took illegal drugs.
An investigation is underway after an ambulance was called to an address in St Lawrence just before 2:30am on Saturday.
Three men are being treated in hospital for what is believed to be the effects of MDMA. Police have not said how old they are.
A woman and three men, all aged between 17 and 26 years old, have been arrested on suspicion of supplying drugs.
Officers are searching several addresses.
Jersey Police is reminding islanders of the dangers of taking MDMA. Anyone who has used the drug and feels unwell should seek medical attention.
Anyone with information about the ongoing investigation is asked to call 01534 612612 or contact Crimestoppers anonymously.
Jersey couple donates £1m to Southampton medical research centre
Extra domestic abuse support as World Cup kicks off
Unclaimed CI Co-op cash funds community projects
Jersey coming together to save wedding after fire
Victoria College considers opening sixth form to girls
Soft play, serious training for Jersey's firefighters
Women break records in the States Assembly this term
No change after St Helier Central vote recount
