SLIPPERY ROCK, Pa. - Police found a 10-year-old boy awaiting a heart transplant by finding his mother's cell phone with global-positioning technology, a technique usually used to find criminals.

John Paul May, of Harrisville, had the successful surgery at Children's Hospital of Pittsburgh on Saturday night, but came dangerously close to being passed over for the donor heart until police tracked down him and his mother at a university jazz festival.

The hospital called state police Saturday afternoon because officials couldn't reach May's parents to let them know a donor heart had been found. When police couldn't find the boy or reach him by phone, they contacted Sprint to get the coordinates of his mother's cell phone.

"The only time you can use it is life or death, or to track someone wanted in a homicide," state police Cpl. James Green said. Otherwise, police must get a warrant from a judge.

Using the coordinates, state police tracked the phone to a Slippery Rock University building. Police stopped the jazz concert and announced they were looking for May and his mother, Sue.

The crowd of about 500 gave the boy a standing ovation as he left, said Steve Hawk, a music professor who conducted the concert.

"I've been in the entertainment business for 30 years and never had such an emotional, shocking event happen at something live," Hawk said.

May was listed in critical but stable condition yesterday, according to a hospital spokesman.