LAREDO — The body on the steel table was a Hispanic woman, probably in her 20s, found on an isolated Texas ranch. In the light of a large bay window overlooking scrub brush and mesquite in the shimmering heat, Dr. Corinne Stern quickly determined that the cause of death was exposure.The medical examiner’s next quest was harder: Who is she?After photographing a silver-rimmed tooth, the woman’s blue-and-green striped shirt and an earlobe with three earrings, Stern searched the clothing. She found a wallet-sized photo of a young girl and a scrap of paper with several phone numbers.Wasting no time, Stern left the autopsy suite and summoned one of her Spanish-speaking investigators. She punched a number into her office phone; a man answered, “Bueno.”“I have a young lady in my office and we found your telephone number,” she said. “Are you missing a relative or do you know someone who may have been carrying your phone number?”As the medical examiner for Webb County, a 3,400-square-mile jurisdiction of 262,000 residents in South Texas, Stern works in a grim corner of the national debate over illegal immigration — identifying the dead.Her struggle to put names to the bodies offers a glimpse into how intractable the border crisis is as it strains the services of South Texas counties. Stern, who estimates that the task takes up 25 percent of her office’s resources, is dealing with migrants from at least six countries, confronting bureaucratic and linguistic hurdles all along the way.She has conducted at least 400 autopsies of immigrants since becoming Webb’s medical examiner in 2006. On any given day, Stern plays the role of forensic expert, homicide detective or even diplomat, asking the governments of Mexico, El Salvador, Guatemala and other nations for help in naming the dead and getting their remains home.“I’m the last doctor they will ever see,” Stern, 48, said of the victims. “My job is bittersweet. I bring families closure, but I also end their hope.”The work is time-consuming and costly. A Texas sheriff’s coalition estimates that each dead crosser costs local authorities at least $5,000, including the burial of some who go unclaimed or are never identified. Foreign governments and relatives of the victims pay to repatriate the bodies.In the last 15 years, more than 5,000 migrants have died crossing into the U.S. from Mexico, according to the Department of Homeland Security. At least 225 have perished since January.Almost all of Stern’s victims are adults. The thousands of unaccompanied children who have crossed the Mexico border in the past year are more likely to surrender to authorities, while adults try to avoid detection. Stern has autopsied three juvenile border crossers over the last 18 months.Stern relies on a small staff — five investigators and autopsy technicians, as well as a cadaver-tracking dog named Rufus. The challenge is evident in a 6-inch-thick binder of missing persons reports and a large dry-erase board for tracking 35 John and Jane Does who have arrived from Webb and the nine other Texas counties she serves under contract. She says she has determined the identities of more than 60 percent of border crossers.Since January, Stern has autopsied 92 border crossers. She has received so many bodies that she declared an emergency in June and obtained a second portable cooler to store corpses.Calls to retrieve bodies in her own county come at all hours, but Stern usually won’t send her staff out after dark. The terrain is too rough, and there are rattlesnakes, not to mention the risk of getting washed away. Last month, while retrieving a “floater,” Stern fell into the Rio Grande and had to scramble back to shore.On July 21, she finished autopsying a Webb County resident whom she determined had died of a heart attack and then turned her attention to two dead immigrants, both discovered in remote parts of Brooks County without identification.Corpses by the dozenSince January, Brooks County has sent her 47 corpses, many of them skeletal remains like these, found by ranch hands, sheriff’s deputies or the border patrol.Clad in brown University of Texas scrubs, a blue surgical cap pulled tight over her auburn hair, and latex gloves, Stern stepped to the right of technician Mary Wickstrom, who was inspecting remains in an opened black body bag. Under the bones, dozens of beetles and bugs scurried about before flittering to the floor. Stern leaned in, oblivious to the insects and the miasma of human decay.“How is my patient?” she asked.As a sign of respect, Stern never uses the words “corpse” or “body.” The remains are patients, decedents or individuals.“I can’t tell if it is black or brown,” Wickstrom said, dusting off the woman’s dark mat of hair. Stern peered closer. “Black,” she said.Wickstrom pointed to the table behind her, where she had arranged the woman’s mud-caked shorts, shirt and a bra.“Looks like it’s rimmed in rhinestones,” she said.“Might be a bathing suit top,” Stern replied. “Excellent.”Stern always asks relatives what their loved one had last been wearing. A rhinestone-studded bra might prove to be a key clue helping solve a case.As Wickstrom finished with the hair, a scrap of paper fell to the table. The tech picked it up; it had a partial phone number on it.“Not a full number, but maybe we can do something with it,” Stern said, inspecting the scrap.Wickstrom discovered a set of upper dentures, two of which were emblazoned with gold-colored stars.The dentures, the bra, the scrap of paper — all would prove critical: The body was tentatively identified as a 27-year-old Guatemalan by her husband after he checked photos of the dentures and a pair of boots. Over the years, Stern has identified bodies thanks to an engraved wedding ring, tummy tuck scars, X-rays of a badly healed broken arm, a tattoo of a Mexican television star and even initials emblazoned on gold-colored tooth caps.Stern is a lifelong Texan whose father was a psychiatrist who fought as an infantryman in World War II and later worked at the Veterans Administration. Her mother served in the Israeli army. At age 4, Stern’s destiny was set; her father told her, quite seriously, that she would be a pathologist.“I have no idea why he picked that profession for me,” she said. “He would take me to visit the lab at the VA, and that kind of nurtured it.”School in Fort WorthAfter medical school at the University of North Texas Health Science Center in Fort Worth and serving her residencies, she became the chief medical examiner for El Paso County. In 2006, she took the job in Webb County, lured in part by the chance to establish the jurisdiction’s medical examiner’s office.The morning after autopsying the two border crossers, Stern checked out a homicide scene and then oversaw the release of two immigrants’ bodies to a funeral home hired by the Mexican government. Foreign governments are responsible for the paperwork, including such records as birth certificates, and arranging and paying for the transport of the bodies back home if the families are indigent.After lunch, Stern switched to full diplomatic mode. From her office, she phoned El Salvador’s consulate in Houston.She wanted to check on the status of the woman she had identified the previous Saturday, the one with the unique tooth and photo of the young girl. The man who had answered Stern’s call that day turned out to be the dead woman’s brother.He was able to identify his 26-year-old sister because he knew the name of her 3-year-old daughter — it had been written on the photo — and through that tooth. He told Stern he had last spoken to his sister a few days earlier.To ensure they had the right person, Stern e-mailed photos of the woman and her belongings to Salvadoran authorities to show the brother. She hoped the officials would use discretion — people look different after death, which can shock the family.Stern learned from a Salvadoran official that the consulate had been in touch with the brother and was working to get the paperwork completed. She then raised some problems she was having with the nonprofit group that El Salvador uses to collect DNA samples from relatives of her victims.In September, Stern tentatively identified a 34-year-old immigrant who had the ID and phone number of a friend in his pocket. Stern couldn’t rely on overseas ID, however, and the friend and the man’s family weren’t able to identify the body based on the personal effects. The corpse was too decomposed to lift fingerprints.That left only comparing his DNA to possible relatives. Stern got the results — they were a match. But she couldn’t say to whom. The nonprofit group has refused to provide the names of those they’ve sampled.