Two teenagers have died in a nightclub in Plymouth after taking an unknown substance which they believed was MDMA.
The pair, both aged 19, from Okehampton and Newton Abbot, were found unconscious in Pryzm at around 1.40am on Saturday (9 December.) They were taken to Plymouth's Derriford Hospital, where they were later pronounced dead.
They were reportedly enjoying a night out with a larger group, who are also believed to have taken the substance, though noone else in the group appears to have suffered any ill-effects.
Devon and Cornwall Police are investigating the deaths. Detective Inspector Julie Scoles told Sky News: "It is currently believed that the two men who died were part of a larger group who had taken what they thought to have been MDMA.
"Many of the group were from Okehampton and had visited Plymouth to attend the Basshunter set at the Pryzm nightclub last night."
Police confirmed that an 18-year-old man is in custody. Inspector Scoles added: "We are not currently seeking anyone else in connection to this death, but would like to hear from anyone who has any information that can help us with our inquiries.
"I am urging the public, especially those going out and planning to take recreational drugs, to be aware of this incident and think twice before taking any unknown substance.
"There is always a risk when taking drugs and the only way of staying safe is to avoid drugs altogether."
Pryzm Nightclub said in a Facebook statement they were "devastated" by the deaths. They warned others against taking recreational drugs.
"It is believed that earlier in the night the two men took what they thought to be MDMA and we would urge anyone, especially those going out tonight and who may be planning on taking recreational drugs, to be aware of this incident and to please think twice before taking any unknown substance," the statement read.
They added: "We would like to extend our thoughts and condolences to the families and friends at this very sad time."
The DJ Basshunter, who was performing on Friday , posted on Twitter that he did not know what happened, but hoped "everyone is ok".
The teenagers next-of-kin have been informed, but the victims are yet to be formally identified.