Boy, 3, Drowns in Back-Yard Pool; Sister on Life Support : Tragedy: Two children opened sliding glass door of den while mother and four other adults were indoors. Authorities are investigating.

A 3-year-old boy drowned and his 2-year-old sister was in critical condition on life support systems Monday after they went into a back-yard swimming pool while their mother and four other adults were indoors, police said.

The two toddlers opened a sliding glass door of the den where they had been sleeping with their mother and wandered to the pool only a few feet away, said Joanne Gainey, the owner of the home and the children’s great-great-aunt. Sometime before 10 a.m., her husband Stanley Gainey spotted them lying on the bottom--the boy in the deep end and the girl in the shallow end, she said.

“My husband saw the door open and yelled,” Gainey said, sobbing. “I had just gotten up and was just messing around, talking to my dogs. I heard the yell and then saw my husband carrying the little girl out of the pool.”

Joanne Gainey ran to the pool and saw the boy lying on the bottom of the eight-foot-deep end. She grabbed the pool net and lifted him up until she could reach him.

“He was very cold,” Gainey said. “I could tell right away there wasn’t much life in him. The little girl still had some warmth to her.”

Paramedics rushed the boy, Donald Miller, to Anaheim General Hospital, where he was pronounced dead at 1:15 p.m., Sheriff’s Lt. Dick Olson said. Two-year-old Serena Miller was taken first to Humana Hospital-West Anaheim and then transferred to Children’s Hospital of Orange County in Orange where she was in critical condition Monday night.

Olson said deputies are investigating the drownings. No one has been arrested.

The two Miller children and their baby brother, Michael, 2 1/2 months, had arrived about three weeks ago from Denver with their mother, Amber Miller, to stay with their aunt, Gainey said. Amber Miller’s mother, Nina, also was staying at the house, in the 12000 block of Lorna Street in an unincorporated area between Garden Grove and Stanton.

Another Miller child, Gilbert, 5, remained behind with their father, who lives near Denver, Gainey said.

The Millers planned to stay “long enough for her to get on her feet,” Joanne Gainey said. “She was looking for a job, but having worked only three weeks in her life, as a waitress at IHOP, and having three children with her, it was very tough on her.”

Amber Miller and her three children had been sleeping in a bedroom with Nina Miller. But the two women had argued Sunday night, and Amber chose to sleep in the den, just steps from the shallow end of the pool, Gainey said.

“It was the first time they had ever slept in the den,” Gainey said. “But we thought it was better, until they got things straightened out.”

She remembers that the sliding glass door to the pool from the den was locked Sunday night. “It was locked at 7:30. I remember distinctly checking it,” Gainey said.

The events of the early morning are confused, but Gainey remembers puttering around the house after her husband, a music teacher, left temporarily to go pick up a student, Gainey said. They returned sometime before 10 a.m., she said.

“I don’t know where Amber was; she must have been awake, but it’s all so confusing now,” Gainey said. “She started screaming, and everybody was screaming.”

The two children were naked when they were found, their clothes piled in a heap just inside the glass door to the den, Gainey said. Even though they did not know how to swim, the two children apparently thought about getting into the pool and taking their clothes off first, Gainey figured.

“They had never been in this pool, but I think they had lived around pools before,” said Gainey, sitting in her patio. There is no grass in the back yard; the pool, a cabana and an L-shaped patio cover take up all the room.

The plastic raft that had been left on the diving board was in the pool, leading Gainey to believe Donald had gotten on top of it, at least temporarily.

“I think he must have been on it, then fell off,” she said.

The commotion in the back yard brought several neighbors, all of whom tried frantically to help with cardiopulmonary resuscitation, she said. A neighbor identified only as Artie jumped over the fence and helped take the boy across the street to a registered nurse, but she was not at home, Gainey said.

Amber Miller was “in hysterics, telling everyone that if the police did not take her she was going to commit suicide,” Joanne Gainey said. “She was devoted to those children, completely devoted. They were almost all she had.”

The youngest child, Michael, was taken to Orangewood, a home for abused or neglected children, for temporary safekeeping, Gainey said.

Nina Miller was also hysterical and went with her boyfriend to Lomita to stay with friends, Gainey said.

Although county officials say drowning is the leading cause of death for children 1 to 4 years old, this was the first since June, 1992, when a 23-month-old drowned in a Huntington Beach pool. That September, an adult, 37, drowned in an Anaheim pool.

In 1991, at least eight children drowned in pools throughout the county.

While relatives and friends dropped by to comfort her, Gainey described Donald and Serena Miller as bright, active kids who were “a handful” for their mother.

“Donald was precocious and charming, maybe a little hyper,” Gainey said. “He took his mother’s constant attention. “I can remember kissing him good night last night and saying “Your Aunt Joe loves you.”