LEMON GROVE (CNS) - Detectives sought Friday to determine what led to the apparent dog-bite death of an 8-month-old boy at his family's East County apartment, where three pit bulls were later impounded.

The fatal attack by at least one of the terriers in the 3500 block of West Street in Lemon Grove was reported shortly before 5 p.m. Thursday, sheriff's Lt. Larry Nesbit said.

Deputies and paramedics arrived to find a woman holding the seriously injured infant. The boy was taken to Rady Children's Hospital in San Diego, where he was pronounced dead about an hour later.

"Because the incident involved the sudden or unexpected death of an infant, the sheriff's homicide detail was requested and assumed the investigation," Nesbit said.

Authorities declined to immediately release the victim's name. An investigator with the county Medical Examiner's Office, which generally identifies deceased people following family notification, said the case had been sealed from public disclosure at the request of sheriff's officials.

Investigators interviewed residents of the rental unit where the attack occurred, and animal-control officers took custody of the three male dogs, all of which lived there, the lieutenant said.

The canines were taken to a shelter in Chula Vista, according to Anne Steinberger, communications manager for that South Bay city, which provides animal-control services to Lemon Grove.

The dogs, which are between 3 and 5 years old, will undergo a standard 10-day rabies quarantine at the Beyer Way facility, Steinberger said. How long they will be held thereafter and what ultimately becomes of them will depend on the results of the investigation by sheriff's detectives.

If the animals are classified as "dangerous dogs" due to the fatality, they will be euthanized, Steinberger said.

How many of the three canines were involved in inflicting the child's injuries remained unclear Friday afternoon.

"We don't know if it was one or all of them," Steinberger said.

Shelter officials also had yet to determine if the dogs were neutered or properly licensed.

It was also unclear if criminal charges would result.

Steve Walker, a spokesman for the District Attorney's Office, said the child's death "remains under investigation by (the sheriff's department), with no timeline for them to turn the case over to us."

The probe could take weeks or even months to complete, depending on whether extensive laboratory work turns out to be necessary, Nesbit said.

The sheriff's lieutenant said officials with his agency planned to meet with legal counsel early next week to determine if and when they can release the victim's name, since there are legal restrictions on disclosure of underage crime victims' identities.