A teenager has died in hospital, three days after taking illegal drugs police think were contaminated.
Mark Brown, 18, from Killingworth, North Tyneside, was one of three people hospitalised after suffering adverse reactions in separate incidents.
A 27-year-old Newcastle woman remains in a critical condition. A third man aged 22 was released after treatment.
Northumbria Police believe tainted batches of cocaine, amphetamines and ecstasy may be on sale in the area.
A force spokeswoman said Mr Brown died in Newcastle General Hospital overnight.
She added: "Mark Brown's family are naturally distraught at what has happened.
"A post-mortem examination is being carried out and forensic tests are ongoing to identify whether the drugs are from the same batch."
Detectives described the separate incidents in Newcastle and North Tyneside as "highly unusual".