"Kallie," a 7-year-old German shepherd, and her handler, Nancy Hachmeister of Layton, have returned to Utah after participating in a successful search for an Arizona toddler, who was missing for four days.

Derrek Clay, 2, was found alive late Tuesday in desert terrain near Casa Grande, Pinal County, said Margaret Gregory of the management committee for Rocky Mountain Rescue Dogs.An all-volunteer organization whose handlers are mainly located in the Salt Lake area, the group dispatched "Kallie" and Hachmeister and four other dogs and their owner-handlers to Arizona after the youngster and his brother, Damien, 4, wandered away from their trailer home last Saturday.

Casa Grande is located between Phoenix and Tucson.

Damien apparently turned up Saturday before a search was launched and before searchers in a helicopter spotted the 2-year-old's diaper. Kallie found the youngster within a radius of slightly more than two miles from the trailer about 10:15 p.m. Tuesday. The child was dehydrated but is in good condition. He was released from a hospital Thursday afternoon, Hachmeister said Friday.

"It's hard to describe how happy I was. . . . We had been searching for him for about 15 hours," she said, explaining that she had been paired with Jackie Vernon, a local searcher from Casa Grande.

"We heard a faint cry. We stopped and heard another cry. Then we started running toward that direction, but the child didn't cry out any more. I don't even know if he knew we were there. We found him in a real bushy palo verde tree," said Hachmeister by telephone from her home early Friday.

Searchers realize that their efforts might result in a sad outcome. "You try to prepare yourself mentally," said Hachmeister, a systems analyst for the Office of Family Support, Utah Department of Human Services.

When found, Derrek Clay was clad only in a tank-top T-shirt and slip-on sandles. Temperatures were in the 90s during the day and in the high 40s during the night, Hachmeister said.

Gregory said all handlers are on call 24 hours a day, 365 days a year. They aren't paid for their work.

"We usually try to send four to six dog teams in a search-and-rescue operation. We make searches in the wilderness, in urban areas, on water, across avalanches and in all types of disasters. We go out prepared to stay three days and are entirely self-supporting. We are dispatched through an 800 number or through the Salt Lake County sheriff's office," Gregory said.

Other dogs and their handlers who participated in the Arizona search are "Diva," a Bernese mountain dog, and her handler, Rhonda Devereaux; "Corby," a malamute, and Ken Lafazan; "Rusty," a golden retriever, and Jim Dowling; and "Nike," a German shepherd, and Laura Taylor. All are from the Salt Lake area.

Contributions to help defray expenses of the organization are welcome and may be sent to Rocky Mountain Rescue Dogs, P.O. Box 1308, Sandy, UT 84091.

In March 1990 the organization sent four dog teams to Venezuela in search of two college students lost in the Sierra Nevada Norte mountains.