Two 18-year-old female students, who had just started at Newcastle University, were among four people to die in the city after taking what are thought to be illegal drugs, police have said.
The girls, both freshers, were living in the same halls of residence in the city, when they took ill and died on Saturday, according to a report.
Jeni Larmour, from County Armagh in Northern Ireland, who was in her first year studying architecture and town planning, was named as one of the girls who died.
Another student, a 21-year-old male undergraduate from Northumbria University, also died over the weekend after taking what is believed to be MDMA.
And a fourth death, of an 18-year-old man in Washington, Tyne and Wear, has also been linked to the effects of MDMA.
Northumbria Police have made 10 arrests in connection with the deaths and have carried out searches with drug dogs at university halls of residences.
Police said they received the first report at 6.05am on Saturday that a woman had taken ill and was unresponsive at a flat within the Park View Student Village.
Miss Larmour, who moved to Newcastle from Northern Ireland in August was pronounced dead at the scene.
An 18-year-old male, who is understood to be a fellow student, was arrested on suspicion of supplying a Class B drug and has since been released on police bail.
The following day at 1.10pm police received another call to the same building on Richardson Road in the city where they found another 18-year-old woman who was pronounced dead at the scene.