A post-mortem examination carried out on the remains of Co Galway student Patrick Halpin in London has been unable to establish the cause of his death.
The 18-year-old's body was found off Leicester Square last Thursday, after he went missing on a night out while on a college visit to London with the DCU Drama Society.
The post-mortem was carried out at Westminster mortuary on Tuesday.
Police are now awaiting the results of further tests.
The teenager will be buried on Sunday following funeral mass at St Brendan's Cathedral in Loughrea, Co Galway.