A baby boy has died after being injured by a family dog in Bangor, authorities said Sunday.

Bangor police said in a statement that they and the Bangor Fire Department responded to a call on July 29 about an infant injured by a family pet at a Bangor home.

Matthew Costello, assistant fire chief, said Sunday that the baby was a 21-day-old boy and the pet was a dog. Costello did not know the breed of the dog.

The infant was taken to Eastern Medical Center in Bangor and died at the hospital, police said. The incident is under investigation by the criminal investigation division of the Bangor police.

Police did not release any further information.

Morning Sentinel Staff Writer Madeline St. Amour contributed to this report.