A teenager left her dead baby in a hotel room after giving birth during a school trip to London.
The baby was discovered by staff at the Days Hotel in Hounslow, West London, 10 days ago.
The girl, who came from a school in Barrie, Ontario, had already flown home with her school party by the time the baby had been discovered.
The baby was not premature and did not have any obvious injuries. A post-mortem examination has failed to identify the cause of death.
The girl was met by police officers at Toronto’s Pearson airport and was taken to hospital for treatment. The girl could face charges.
Scotland Yard is waiting for more tests to be carried out on the baby, which could take weeks.
A Scotland Yard spokesman said: “The child was pronounced dead at the scene and a post mortem took place at Great Ormond Street Hospital on Friday.
“However, it proved inconclusive and we are awaiting further tests to establish the cause of death.
“The investigation is been conducted by detectives from the Child Abuse Investigation Command in liaison with the Canadian authorities.
“The identification of the mother is known, but no arrests have been made.”