A torched scooter may hold the key to finding the killers of a man with autism shot dead on his doorstep, police say.
Chad Gordon, 27, was shot in the head at close range after answering his door in Haringey, north London, on 18 May.
Officer believe Mr Gordon's killing was a case of mistaken identity.
Two suspects, wearing black clothing, fled on a scooter which was dumped and set on fire in nearby Tottenham Marshes, the Met said.
Armed officers were called after reports that shots had been fired just after 20:20 BST.
Mr Gordon was found by medics with a gunshot wound to the head and pronounced dead at the scene.
Det Ch Insp Andy Partridge said: "We know that Chad's killers used this scooter to flee the scene of the murder and that around 30 minutes later it was left in Tottenham Marshes and set on fire.
"A scooter being set alight would have stood out. We know two black males, aged in their late teens or early 20s, were seen to leave the location where the moped was on fire.
"They made off on foot and headed towards the Green Bridge a short distance away. I need help from the public to tell me where they went after reaching the bridge."
No arrests have been made.