EDINBURG, Texas (AP) — When authorities found an 11-year-old Guatemalan boy's body about a mile from Texas' southern border, they also discovered his brother's Chicago phone number scribbled on the inside of his belt buckle.

The boy, wearing "Angry Birds" jeans, black leather boots and a white rosary around his neck, had apparently gotten lost on his way north from his native country and was found about two weeks ago, alone in the brush less than a mile from the nearest U.S. home, a South Texas sheriff said Monday.

While hundreds of immigrants die crossing the border each year, the discovery of Gilberto Francisco Ramos Juarez's decomposed body in the Rio Grande Valley on June 15 highlights the perils unaccompanied children face as the U.S. government searches for ways to deal with record numbers of children crossing into the country illegally.

"Down here finding a decomposed body ... we come across them quite often," Hidalgo County Sheriff Eddie Guerra said, adding that this was the first child immigrant his office has found since he became sheriff in April. "It's a very dangerous journey."

More than 52,000 unaccompanied children have been apprehended entering the U.S. illegally since October, creating what President Barack Obama has called an "urgent humanitarian situation." On Monday, Obama asked Congress for more money and additional authority to deal with the surge of youths, mostly from Central America. Obama wants flexibility to speed the youths' deportations and $2 billion to hire more immigration judges and open more detention facilities.

The number of unaccompanied immigrant children picked up along the border has been rising for three years as they fled pervasive gang violence in Honduras, Guatemala and El Salvador. More recently, children and parents have said they heard children traveling alone and parents traveling with young kids would be released by authorities and allowed to continue to their destination.

Many of the children turn themselves in to the first law enforcement person they see, so Guerra said it was unusual to find a child in this more remote area — near La Joya, about 20 miles west of McAllen. Sometimes smugglers, known as coyotes, leave people behind if they can't go on; other times a group may scatter when authorities approach.

Investigators were able to reach the boy's brother in Chicago; his phone number was one of three on the boy's belt. It's not uncommon for immigrants to put relatives' phone numbers on their clothing because scraps of paper can get lost or wet during their journey.

The boy's brother gave authorities his father's phone number in Guatemala, and the dad identified the boy's personal items.

The cause of death has not been determined, but authorities suspect heat stroke, Guerra said. The boy was no longer wearing a shirt when he was found. An autopsy did not find signs of trauma, and the pathologist estimated the body had been there for about two weeks.

The boy's family in Huehuetenango, Chiantla, Guatemala, had last heard from him about 25 days before his body was found. At that time, he was in Reynosa, Mexico, waiting to cross the border. His father told authorities the boy was traveling with a coyote.

Although the number of immigrant children who have died crossing into Texas was not immediately available, such discoveries are not unheard of.

About 445 immigrants died along the U.S.-Mexico border last year, according to the Border Patrol. The Pima County medical examiner in Arizona, which is the perennial leader in immigrant deaths, recorded 168 of the deaths; of the 70 where an age was confirmed, none were younger than 13.

Immigrant deaths in the brush in Hidalgo County occur from time to time, but more common are drownings in the Rio Grande. Brooks County to the north has more immigrant deaths in its vast unpopulated ranches.

Dr. Lori Baker, an anthropologist at Baylor University, has spent years exhuming immigrant graves along the border and trying to identify them. Earlier this month, she spent two weeks exhuming 52 graves at a cemetery in Falfurrias, the Brooks County seat. She made a similar excavation last year. Baker recalled exhuming an infant, a 2-year-old, a 6-year-old and a preteen.

Baker said children's bones are small, so they aren't easily seen in the brush.

"There are going to be many more if we can find their tiny bodies."