Police have issued a warning over a possible batch of “particularly strong drugs” as a woman died and two others became unwell after taking the tablets.
Northumbria Police launched an investigation after a woman in her 30s died and two others became unwell after the drugs, believed to be blue diazepam tablets, were circulated in Southwick, Sunderland.
Officers said they suspect all three had taken the tablets.
A 58-year-old man was arrested on suspicion of being concerned in the supply of drugs and has been released under investigation.
A statement from Northumbria Police on Twitter said: “Today, we are warning anyone in possession of these tablets not to take them.
“Our thoughts go out to the loved ones of the woman who has sadly died and we are continuing to establish the circumstances around her death.
“Although enquiries are at an early stage, the risks of taking illegal drugs are well documented & we would urge people not to take them & dispose of them safely.
“Any info can report via ‘Tell Us Something’ page on our website or via 101.”