WAI'ANAE — The state Department of Human Services has launched an investigation into Sunday's fatal dog attack of a 2-month-old boy in Wai'anae.

"We have launched an investigation into the dog attack," department spokesman Alan Eyerly said today. "We are definitely investigating."

Asked what areas are being investigated, Eyerly said, "possible lack of child supervision."

"We have no information on this dog," spokeswoman Kawehi Yim said today. "No microchip, no tag, nothing. There's no identification on this animal."

Before Sunday, Humane Society officials had not received any complaints about the animal, Yim said, and it has behaved while at the Humane Society.

"We have had no problems with it," Yim said.

The mixed-breed dog remains at the Hawaiian Humane Society today as officials try to identify its owner.

Humane Society officials do not know the dog's approximate age or breed.

It is being kept in isolation at the Humane Society at the request of the Honolulu Police Department "because it is involved in the death of an infant," Yim said. "It definitely is a police matter. We'll be in discussion with HPD regarding the next course of action."

HPD officials did not immediately respond to requests for information about the case today.

The Humane Society would not allow media to photograph the dog today or even release a photo of the animal.

The dog, a female of mixed breed, was taken away at 4:30 a.m. yesterday.

The Honolulu medical examiner's office identified the infant as Iokepa Liptak. An autopsy is scheduled for today.

The baby's mother also was bitten and taken to an area hospital, said HPD Maj. Frank Fujii.

Bryan Cheplic, city Emergency Services Department spokesman, said the woman was in stable condition. An ambulance crew had been called back to the home less than an hour later to treat another adult, who was not taken to a hospital but also was injured in the attack, he said.

An autopsy will be conducted today on the infant. Until then, police and medical examiners are classifying the case as an unattended death, meaning no cause of death has been determined. Fujii said the investigation continues.

In the quiet neighborhood on Kakaiapola Street where the family lives, many of the residents have lived in their homes for years. Neighbors did not know the names of the occupants or how many people lived in the small, green house with a carport.

Jennifer Archer lives next door. Archer said she heard a commotion around midnight after she came home from work at McDonald's.

"I heard a woman screaming, 'My baby, my baby got bit in the head,' " Archer said. "I called 911 and I saw a woman in the house call 911. I can see from my home into theirs."

Alanna Matavao, who lives on Kakaiapola Street, said she woke up to hear a lot of screaming coming from the home.

"I don't know the family," Matavao said. "I saw the baby and the lady in the ambulance. We don't pay attention to the house. We only hear the baby crying and some toddlers once in awhile."

Neighbors said the dog, a black mixed breed they described as a pit bull, barked a lot when someone walked by the house. Archer said there were four dogs living in a kennel in the rear of the property.

Until a month ago the black dog lived in a tarp-covered chain link fence kennel in the backyard with the others, said neighbor Bob Vidinha, who lives behind the family.

Vidinha said every time he goes into his yard to water his plants, the dogs bark and jump at the cage.

"The dog was in the kennel 90 percent of the time, except for the past month, and then he was in the yard," Vidinha said.

A woman, who didn't want to be identified, came out of the house yesterday afternoon and would not comment about the death. She said: "Everyone is traumatized. It's just too sensitive."

A neighbor across the street, who identified herself as Roberta, said the dog would bark when she went to her car parked across the street.

"I wouldn't trust that dog. He'd growl at me," she said. "If you raise a pit bull correctly, they can be good dogs. They get a bad rap."

The city's dangerous-dog law provides for jail time and fines if a dog owner's animal inflicts bodily harm. Last year a Kahala dog owner was sentenced to six months' probation and community service after her rottweiler attacked two children, ages 2 and 4, in separate incidents on Kahala Beach.

In 2004 the Maui Humane Society impounded a pit bull that mauled a woman and tore off most of her scalp.

Yim said no one at the Humane Society could remember a dog attack like yesterday's.

The Humane Society issued 23 warning notices to dog owners and 22 citations that required the owners to appear in court for violations to the city's dangerous-dog law, Yim said.

"This is the first time on O'ahu as far as I can remember where a dog killed someone," Yim said. "Most of the time it's just dog bites. This is just awful. I feel for the family."

The Humane Society is working with police. No decision has been made on what to do with the dog.

Reach Suzanne Roig at sroig@honoluluadvertiser.com and Dan Nakaso at dnakaso@honoluluadvertiser.com.