Two men have been arrested on suspicion of Class-A drugs offences after six people died in Essex within two days.
Detectives have been investigating the suspected drugs-related deaths of three men and three women at the end of last month.
All the victims died in neighbouring towns within 10 miles of each other – Canvey Island, Benfleet, Leigh-on-Sea and Westcliff-on-Sea, a suburb of Southend.
Health chiefs warned people not to buy drugs for fear a bad batch could be responsible for killing users.
A 26-year-old from London and a 29-year-old from Grays, Essex, were arrested in Barking on suspicion of possession with intent to supply Class-A drugs, and are both in police custody.
Police said tests to identify the drug or substance involved were under way but their focus remained on Class-A drugs.
Additional reporting by the Press Association
