A brick thrown through the window of a family home in Antrim, which landed in a baby's cot, could have caused "serious injury", police have said.
Two windows of the house in Tarragon Park were smashed at 02:20 BST.
The one-year-old baby was not in the cot at the time because of illness, and the parents had taken the child into their own bed, said Sgt John Hamilton.
"These reckless actions could have caused serious injury had this not been the case," he said.
The family are originally from Poland.
Police said they were treating the attack as a hate crime.
Supt Emma Bond said: "The victims were very distressed and upset.
"It's a reckless attack which could have had devastating consequences. These sorts of incidents should be condemned and I appeal for anyone with information to come forward."