An attack on two Border Patrol officers reportedly occurred Sunday morning, but was not announced publicly until later Sunday evening.

While responding to “activity” in the Van Horn Station area of western Texas, near Interstate 10, the two agents were attacked. Agent Rogelio Martinez, 36, died of his injuries, while his partner remains in serious condition.

No details were released on how the incident occurred, but it was reported that authorities are searching Texas’ Big Bend for potential suspects and witnesses.

A press release from the Border Patrol included the following statement: “Agent Martinez’s partner reported that they were both injured and in need of assistance. Responding agents provided immediate medical care, and transported both agents to a local hospital. Big Bend Sector was later told that Agent Martinez expired from his injuries. His partner remains in the local hospital in serious condition.”

Soon after the news broke, President Trump posted a response on Twitter, saying, “Border Patrol Officer killed at Southern Border, another badly hurt. We will seek out and bring to justice those responsible. We will, and must, build the Wall!”