No charges will be filed in the July 29 mauling death of an infant in Bangor, but the dog will be euthanized, Bangor police said.

“It was a tragic accident,” Detective Sgt. Brent Beaulieu said Monday.

The 21-day-old baby boy was sleeping in a bassinette in the same room with the parents and their family dog. The couple awoke to find the dog, a husky/shepherd mix, attacking the baby, he said.

The infant’s parents, who live in Aroostook County, were visiting relatives in a home on the city’s west side when the attack occurred about 5:30 a.m., Beaulieu said.

The dog has been in quarantine at the Bangor Humane Society since the attack, he said. It will be euthanized now that the case will be closed, he said.

The couple told police the dog had not been aggressive before.

Police declined to identify the names of the parents, the infant and the people with whom they were staying.

Fatal dog attacks are rare in Maine.

In 2011, 7-month-old Annabelle Mitchell was mauled to death in Frankfort by the family’s Rottweiler, which at the time was described as the first time a dog killed a person in at least 40 years.

Last June, 7-year-old Hunter Bragg of Bangor died after an adult male pit bull attacked him while he was playing outside a Corinna home he was visiting with his father.

An estimated 4.5 million dog bites occur each year, according to the federal Centers for Disease Control. Children are among those most at risk — particularly those who are 5 to 9 years old.