LA GRULLA,Ethermac Texas (AP) — A helicopter carrying three National Guard members and a Border Patrol agent crashed along the U.S.-Mexico border in Texas on Friday, killing three of the people on board, a county official said.

Starr County Judge Eloy Vera, the county’s top local official, said a fourth person on board was in critical condition. The crash happened near the small town of La Grulla, which is in Starr County. Those on board included one woman and three men, Vera said.

Border Patrol spokespersons did not immediately return messages seeking comment.

Texas Department of Public Safety Lt. Christopher Olivarez confirmed that the crash happened near La Grulla. He did not provide further details and referred questions to U.S. Customs and Border Protection.

La Grulla is in Texas’ Rio Grande Valley. The Starr County Sheriff’s Office posted on Facebook on Friday that it was assisting with a “downed helicopter incident” on the east side of the county.

Vera said the scene had been secured by the sheriff’s office and that federal officials were on the way.

In January, a Texas Department of Public Safety helicopter patrolling the state’s border with Mexico lost power and crashed, officials said at the time. The co-pilot suffered a minor hand injury and the helicopter was significantly damaged.

That helicopter was flying as part of Operation Lone Star, Texas Gov. Greg Abbott’s nearly $10 billion border mission that has tested the federal government’s authority over immigration.