Tujunga Neighborhood Shaken by Drowning of Twins in Swimming Pool : Tragedy: The possibility of neglect by parents is being investigated. A resident had called a county child-abuse hot line earlier in the day but was told agents were busy.

Residents of Silverton Avenue in Tujunga like to think of their street as a children’s haven because of its relative isolation, thick trees and vines, and rambling houses replete with stone fences, hidden gardens and creaking wooden gates.

As many as 20 youngsters at a time congregate in the street, apparently protected by nearby parents and a sign that warns motorists, “Slow. Children at Play.”

But tragedy invaded Silverton’s quiet world Wednesday evening when a pair of identical twin toddlers, Tyler and Quinn Gugler, were found drowned in a neighbor’s fenced-in pool.

How the 2 1/2-year-olds managed to enter the pool area--which is enclosed by a concrete-block wall, a 6-foot-tall, self-latching wooden gate and a cyclone fence--remained under investigation Thursday, said Los Angeles Police Lt. Bernard Conine.

The pool’s owners, Donald and Francys Abbott, both 81--whose daughters described them as heartbroken over the incident--were watching television and heard nothing until paramedics arrived about 7:30 p.m.

Police were also investigating the possibility of neglect by the twins’ parents, Diane and George Gugler, because neighbors said the twins often wandered near busy streets and into nearby homes without apparent supervision, Conine and detectives said.

One neighborhood father who asked not to be named phoned the county’s child-abuse hot line just hours before the drowning Wednesday because the twins had climbed onto his garage-top patio for the second time in a week. When the twins climbed onto his patio last Sunday, the homeowner said, another neighbor across the street stopped them before they fell off a wooden railing.

“I was concerned about my liability as well as their well-being so I called, I wanted it on record,” said the neighbor, who also called the police.

He said he phoned the county Department of Children’s Services hot line about 2 p.m. and was told that agents were busy, that he would be called back in an hour if there was no emergency.

The neighbor said he waited until 3 p.m., and then had to leave.

“I got home at 7:30 and they were gone,” he said of the twins. “It’s a shame.”

A Children’s Services spokeswoman, Lili Ahmadi, said an internal investigation was being conducted to determine whether the man’s call should have been treated as an emergency. The agency unsuccessfully returned the call twice Wednesday afternoon and finally reached the homeowner Thursday morning, when he told the caller it was too late, Ahmadi said.

The Guglers were in seclusion Thursday.

An attorney and family friend, John L. Simonson, told reporters that the couple was too grief-stricken to comment on what he characterized as unfounded neighborhood gossip. “After the deaths of their babies they don’t feel compelled to confirm or deny” any allegations, Simonson said at a news conference outside the Guglers’ home.

“There is one neighbor who has complained” to county child welfare authorities “of some lack of supervision,” he acknowledged. “These reports are as of yet unfounded, and the person making them is of unknown character.”

Simonson said the family decided to call the news conference because they were concerned by television reports of the drowning. He did not elaborate, and no one in the family was present.

“The family wants everyone to know how much they love their babies and how devastated they are by the loss,” Simonson said.

John Winchell, a former resident and friend of the Guglers, said the couple were devoted to their five children. They have a daughter in her 20s, a teen-age daughter and a 9-year-old son.

Drowning is the leading cause of death for children 4 or younger in Los Angeles County, although car accidents are a close contender, said Billie Weiss, an epidemiologist with the county Health Department.

Last year, according to a spokesman for the county coroner’s office, 31 children under 18 drowned, the majority of them toddlers.

On Wednesday evening, the Gugler twins and their brother were playing in the family’s toy-strewn yard when their father left for a jog, according to police reports. Their mother was inside the house. The 9-year-old had been told to keep an eye on his brothers, said Police Detective Al Ferrand.

Another detective, Lt. Thomas (Reggie) Maeweather, said that when George Gugler returned from his run about 35 minutes later, the twins were gone and the older boy did not know where they were. He said Gugler then searched the neighborhood and found the twins in the Abbotts’ pool.

Winchell said it was common practice for parents indoors to let their children play outdoors-- secure in the knowledge that someone was keeping an eye on them.

Another neighbor, Robert Shoop, said he allows his 5-year-old son to roam relatively free because he has come to depend on the neighborhood’s other parents.

The redwood gate that seals off the pool can be opened from the outside but the latch is 4 1/2 to 5 feet off the ground, beyond a toddler’s reach, Conine said.

Neighbors, including a lifeguard and a nurse alerted to the emergency by screaming children and the sound of an ambulance, unsuccessfully tried to revive the boys, who were pronounced dead at Verdugo Hills Hospital.

“I was in my living room talking to a neighbor when my son came running in saying, ‘Mommy, mommy! There’s a baby in the pool and we can’t get him out,’ ” said Nadine Castro, the nurse who administered CPR to the twins with neighbor Nicole Chalante, a YMCA lifeguard on maternity leave.

Times staff writer Sebastian Rotella contributed to this story.