Two brothers in Texas have been arrested after authorities say one of them opened fire on a group of migrants getting water near the U.S.-Mexico border, killing one man and shooting a woman in the stomach, according to court documents filed Thursday.

The shooting Tuesday was in rural Hudspeth County about 90 miles from El Paso, where the woman was transported and recovering at a hospital, according to the Texas Department of Public Safety (DPS).

The Texas DPS said the victims were among a group of migrants standing alongside the road getting water when a truck with two men inside pulled over. According to court documents, the group had taken cover as the truck first passed to avoid being detected but the truck then backed up.

Michael Sheppard and Mark Sheppard, both 60, were charged with manslaughter, according to court documents. It was not clear whether either man had an attorney and no contact information could immediately be found Thursday.

Records show that Michael Sheppard was a warden at the West Texas Detention Facility, a privately owned center that houses migrant detainees and contracts with U.S. Immigration and Customs Enforcement.

"This killing was not vigilante justice," Texas Democratic Party Chairman Gilbert Hinojosa said in a statement on Thursday. 

"It was a murder, and it was a hate crime."

U.S. Customs and Border Protection said earlier this month that it recorded 203,597 migrant encounters at the U.S.-Mexico border in August alone and expected the total number of encounters to rise to about 2.3 million by the end of the fiscal year on Friday.

(With input from agencies)