Teenager still alive when car caught fire
A man whose body was found inside a burning car in Londonderry on Saturday was 18-year-old Caoimhin Cassidy Crossan.
Police believe he was "most likely still alive when the blaze started".
The body of Mr Cassidy was found in the car on the Fairview Road in Derry at about 04:15 BST, after it had crashed into a lamp-post.
A post-mortem examination revealed he had not been seriously physically injured in the collision.
Police want to trace anyone who may have been with the teenager when he died.
They said the car, a Mazda 6, was stolen from a house in Oakfield Crescent earlier on Saturday.
Det Insp Michael Winters said: "This was an appalling end to a young life and Caoimhin's family and friends deserve to know how he died.
"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.
"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."
On Monday police had appealed for anyone concerned about a relative or friend who has not been seen in a few days to come forward.
A police missing persons' appeal had been issued for Mr Cassidy Crossan earlier this month.