Police said a teen who was found dead in an car wreck in Derry died an "appalling death," saying he may have been alive before the car caught fire.
The body of 18-year-old Caoimhin Cassidy was found in a passenger seat of a red Mazda 6 which had crashed on the Fairview Road during the early hours of Saturday 1 June.
Detective Inspector Michael Winters: "Initially it was believed that the car had caught fire as a result of the collision, however, the results from the post mortem examination tell us that Caoimhin was not seriously physically injured as a result of a crash, and was in fact most likely still alive when the blaze started.
"Our enquiries to date have established that the Mazda crossed the border into County Donegal a number of times before it was reported on fire at Fairview Road at 4.15am."
The red Mazda 6 car - with registration NHZ 4594 - had been stolen from a house in the Oakfield Crescent area earlier that night.
Police earlier said they received reports the car had struck a lamppost in Fairview Road at around 4am, had caught fire and travelled further into the Galliagh estate before coming to a stop.
The police officer continued: "We are appealing for the public’s help in determining the movements of the vehicle during the early morning hours of Saturday 1 June. We also need to urgently identify any individuals who may have been with Caoimhin on that fateful night.
"This was an appalling end to a young life and Caoimhin’s family and friends deserve to know how he died."
Caoimhin was from Creggan Heights in the city and was known affectionately as 'Toot'. His friends and family made appeals on social media for help in finding him as he had not been in contact with any of them since Friday afternoon, 12 hours before the incident.
Tributes were posted on social media as news of his death spread on Monday night.
Girlfriend Raychel McLaughlin said: "My nightmare has become reality. No words can describe how I feel at the minute.
"Rest in peace baby boy. I will always, always love you."
Detectives can be contacted at Strand Road CID on 101 quoting reference number 316 01/06/19.
Alternatively, anonymous information can also be provided to the independent charity Crimestoppers on 0800 555 111 which is 100% anonymous and gives people the power to speak up and stop crime.