Police are seeking to establish a motive for a hammer attack on a teenage girl at her County Down home.
However, some residents of the Kilcooley estate in Bangor said they believed the attack was random.
The 18-year-old was taken to hospital in a serious condition after being hit on the head. She was later released.
Inspector Jeremy Adams appealed for witnesses. "We are appealing for anyone who knows anything about this attack to contact police urgently," he said.
"It is a very disturbing incident where a young girl is attacked in her house, and thankfully these incidents are rare in north Down."
The teenager was in her flat in the Inishargie Gardens area of Bangor at about 1700 BST on Friday when a man called at her door.
She opened the door and was struck a number of times.
The attacker is described as being 5' 10" tall, of heavy build and wearing a black jacket and black monkey hat.
He may have been seen in the area earlier in the day.
Anyone with information about the assault is being urged to contact the police at Bangor.
Elaine Martin of the Kilcooley Community Forum said it had shocked people in the area.
"Anyone I have spoken to is disgusted - and that is putting it mildly," she said.
"The feeling is that no matter who did this - whether linked to anybody or just an individual - there is no justification at all."