Police chiefs are warning of the dangers of drugs following the death of a woman in Sheffield.
She was rushed to hospital from the Glossop Road area at around 5.30am on Wednesday but could not be saved.
A 20-year-old woman was also taken to hospital on the same day after she too became ill following the suspected consumption of drugs.
She remains in hospital in a serious condition.
The cases are not being linked.
Two people arrested in connection with the investigation, a 23-year-old man and a 20-year-old woman, have been released under investigation while enquiries continue.
They were held on suspicion of supplying a controlled substance.
Temporary Chief Superintendent Shaun Morley said: “Officers are currently investigating the incidents in Sheffield and the circumstances surrounding the death suspected to be linked to MDNA ingestion.
"Specialist officers are now providing support to the woman’s family and our thoughts remain with them at this extremely difficult time.
“Following these tragic events, I would like to urge everyone to be aware of the dangerous risks, both legal and illegal drugs, pose.
"To raise awareness of these risks to drug users, we continue to work closely with our partners in public health to provide advice and support.
“If you or anyone you know has taken a substance and feels unwell, please seek medical advice immediately."
Call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.