Drug link inquiry after Shauna Davies, 15, dies in Caerphilly
Four people have been arrested on suspicion of drugs offences following the death of a 15-year-old girl.
Shauna Davies died in the early hours of Sunday shortly after emergency services were called to Caerphilly Mountain Road.
Four other people were taken to hospital for checks over concerns for their health.
They were arrested on suspicion of being concerned in the supply of drugs.
While they were released as investigations continue, Det Ch Insp Nicola Brain of Gwent Police said officers will look at whether "substances have been a contributing factor" in the death.
"A post mortem examination will be carried out to determine the exact cause of death," she added.
"Our thoughts are with her family and friends at this time."