Labour deputy leader Harriet Harman has appealed for information over the murder of a teenager in south London.
Firefighters found the body of Samuel Ogunro after the fire on Jowett Street in Peckham last Tuesday. He had died of a bullet wound to the head.
Ms Harman, MP for the area, called for anyone with information on the "terrible murder" to contact police.
On Saturday a man, 19, was arrested on suspicion of murder and is being held in a south London station.
A 16-year-old arrested on Wednesday was released on bail.
Ms Harman said: "I am strongly backing the appeal about this terrible murder.
"I am saying listen to what the police have said and do what they ask.
"Do it for the sake of this 17-year-old lad who has been brutally murdered."
Officers said two to three suspects had been spotted running from the Rover car, number plate V683 DPN, while it was on fire.
The vehicle may have been taken away for a time before being returned to the scene prior to the bank holiday weekend, police said.