Penobscot County police said Sunday they were in the midst of a complex investigation into the death of a young boy attacked by a dog in Corinna and would not release additional details until Monday.

Sheriff Troy J. Morton said in a news release that the attack occurred around 5:15 p.m. Saturday at a home on Moody’s Mills Road. When deputies arrived, the 7-year-old boy was already dead, Morton said. No one else was injured in the attack, he said.

Morton said the boy’s identity and the dog’s breed are not being released until the sheriff’s office has collected more information. The dog has been impounded, he said.

“I can appreciate the interest in this incident; however, it is a complex incident and we believe in providing accurate information,” Morton said Sunday evening in an emailed response to questions.

Raymond Freve, interim superintendent of Regional School Unit 19, which includes the towns of Corinna, Dixmont, Etna, Hartland, Newport, Palmyra, Plymouth and St. Albans, said Sunday evening that the victim did not attend classes in his district.

“He was there visiting a student from our district (when the dog attacked him),” Freve said.

The student being visited attends Corinna Elementary School, Freve said. RSU 19 will have grief counselors available Monday at the school for any student or staff member who might need to talk to someone.

Freve said he was shocked when he heard the news from the elementary school principal. “It’s just horrible,” he said.

Jim Emerson, a volunteer firefighter in Corinna and a former police officer there, said he is familiar with the residence where the attack took place. The split-level home is located on a gravel road and is in poor condition, he said. There are eight or nine homes – including a couple of former working farms – on Moody’s Mills Road.

“I don’t know who lives there now,” he said.

Corinna is a small, rural town with a population of about 2,200. It has one restaurant and two small stores.

Barbara Marshall, a selectwoman in Corinna, said she was unfamiliar with the family who lives in the home.

“It’s a very sad situation,” said Marshall, who noted that the region is still grieving the death of a 4-year-old St. Albans boy who drowned last month in a manmade pond.

“There hasn’t been a lot of good news around here for a while,” she said.

Contacted at home, the wife of the town’s animal control officer said they had been instructed not to comment on the case because of the ongoing investigation.

According to the federal Centers for Disease Control and Prevention, about 4.5 million people are bitten by dogs each year in the U.S. About one in five people becomes infected, placing the victim at risk for illness or even death.

Children are most at risk for dog bites. Among children, the rate of dog-bite-related injuries is highest among those 5 to 9 years old, the CDC says. More than half of dog bite injuries occur at home and involve dogs that are familiar to family members.

In a 2011 dog bite case in Maine, 7-month-old Annabelle Mitchell of Frankfort was mauled by the family’s Rottweiler. Her mother, Katrina Mitchell, was drunk and passed out on a couch at the time and the baby’s father was not home, the Portland Press Herald reported.

The dog was euthanized, and the mother was later sentenced to three months in jail after pleading no contest to endangering the welfare of a child.