Scott Vineer, 17, critical after Lisburn assault
A teenager found unconscious in Lisburn was kicked repeatedly in the head, police have said.
Scott Vineer was found lying in the grounds of a disused furniture showroom close to the Lagan towpath.
The 17-year-old, who is autistic, is in a critical condition in hospital.
His mother raised the alarm at 22:00 BST on Thursday after he failed to return home from college. He was not found for another 24 hours.
Detective Inspector Chris St John said his mother had told police "it was very out of character for Scott not to come home as his autism meant he required a degree of structure and routine to his day".
A police spokesman said they were shocked he could go missing in broad daylight from the centre of Lisburn.
Detectives are trying to establish his movements after he was last seen leaving college on Thursday afternoon.
No motive has yet been established for the attack on the teenager, described as a "gentle giant".
Detectives are not aware if anything was stolen from him, and they say there is nothing to suggest a sectarian motive.
Chief Inspector Darrin Jones said it was a "brutal and senseless attack on a vulnerable young man".
"We know local people are disgusted by what has happened and want to do anything they can to help us bring those responsible for this sickening attack to justice," he said.
"That is why I am asking anyone with any scrap of information, no matter how insignificant it may seem, to contact us. Help us find those responsible."