President Donald Trump highlighted news of a border patrol officer who was killed while patrolling the southern border of the United States.

“Border Patrol Officer killed at Southern Border, another badly hurt,” he wrote on Twitter. “We will seek out and bring to justice those responsible.”

According to the National Border Patrol Council, a group of illegal aliens ambushed two agents and beat them with rocks, killing Agent Rogilio Martinez. The second agent was hospitalized.

Trump responded to the attacks by vowing to build the wall on the southern border.

“We will, and must, build the Wall!” he wrote.