Hundreds of people die or are reported missing each year while trying to cross the border illegally, but there’s no accurate count due to a patchwork of practices along the border.

University of Arizona researchers hope to change that with a new best-practices manual designed to standardize the identification and examination of unauthorized border-crosser remains. A standard criteria along the entire border would help ensure an accurate count of bodies examined and a better estimate of how many people are dying trying to cross the border, said Raquel Rubio-Goldsmith, a forensic investigator with the Binational Migration Institute at the University of Arizona.

Since 2000, more than 2,000 people have died while crossing the border in Arizona, until recently the busiest spot for crossings and deaths. But aside from the Office of the Medical Examiner in Pima County, which is seen as the gold standard, no other entity systematically tracks how many immigrants’ remains are recovered.

As migration patterns shift, so has the share of people dying in Texas — particularly in Brooks County, where most die while hiking through rugged ranchland trying to circumvent a Border Patrol checkpoint. So far this year, the remains of about 30 people have been recovered in that county alone, compared to about 50 in Southern Arizona.

And many of them are not identified.

Part of the problem is a lack of training and resources. It took years for the Pima County Medical Examiner’s Office to develop supplementary autopsy report forms that help with future identification, to learn about fingerprinting techniques when remains are mummified and to continuously update a database with information, including GPS coordinates, of undocumented border-crosser remains.

Of 35 counties that responded to a survey that helped shape the best-practices manual, only 40 percent said they consistently retain records of the unidentified.

In Brooks County, for instance, officials initially didn’t perform autopsies or collect DNA samples on all remains of probable border crossers. They were often buried in unidentified graves, and in some cases, multiple remains were interred together.

There are many layers to identifying unauthorized border crossers, said Gabriella Soto, a graduate research assistant who worked on the manual.

Often, remains are skeletonized or mummified due to the exposure to the elements and they are found in remote areas without family or friends to tell officials what happened.

“To actually identify them or to have any hope of identifying them beyond correlating their identities with missing persons reports, special forensic processes are needed,” she said, which many of the smaller counties don’t have access to.

The manual, which was seven years in the making and will be translated into Spanish, includes recommendations for how to identify possible border crossers, best forensic practices and the need for DNA testing. It also calls for the use of a centralized database that matches missing person reports to records of unidentified remains, a task already being led by Tucson’s Colibrí Center for Human Rights.

In Texas, it has already been put to use.

It helped change a law that will make death records of unidentified people publicly available after one year, as opposed to the current requirement of 25 years. And last month, it was used to help train Brooks County officials and deputies and offer an overview to Border Patrol agents, said Eddie Canales, director of the South Texas Human Rights Center, which was created in 2013 as a response to what was happening in Brooks County.

Standardizing procedures across the border is key to understanding the magnitude of the problem, he said. “The general public and policymakers in Washington, D.C., don’t seem to have an idea of the mass disaster and humanitarian crisis happening on the border,” he said.

Canales’ center will also partner with the Binational Migration Institute and other border groups in the United States and Mexico for a conference in February to discuss the manual and best practices.

“It’s crucial that we have the most accurate information possible to present to the public so they can make the kinds of decisions that are needed to stop the deaths,” Rubio-Goldsmith said. “These are deaths that do not have to happen.”

Contact reporter Perla Trevizo at ptrevizo@tucson.com or 573-4213. On Twitter: @Perla_Trevizo