EDINBURG – Texas Crime Stoppers is offering a $20,000 reward for information in the attack that left one Border Patrol agent dead and another seriously injured.

More than 120 pictures of fallen agents are framed in the National Border Patrol Council Office.

“You have Susan Rodriguez and Ricardo Salinas, they were murdered out in San Benito in 1998,” Chris Cabrera, with the Border Patrol Union, said.

Another picture will soon be added to the memorial.

Rogelio Martinez, 36, of El Paso died while on duty on Sunday near Van Horn, Texas.

“So far it seems like an ambush,” Cabrera said.

He said Martinez went to check out a sensor that had gone off near I-10. He called his partner for help tracking the people who set off the alarm.

When his partner arrived, Martinez was unconscious with multiple head injuries. The agent also called for backup but he too was unconscious when more help arrived.

“They were struck multiple times with large rocks, multiple attackers, and it did a fair amount of damage to them,” Cabrera said.

Martinez leaves behind a son and a fiancé. The FBI is leading the search for the killer or killers.

“Our agent was murdered. And it was an attempted murder on the other agent. Somebody murdered our agent. And we need to catch this individual or individuals and make it right,” he said.

Cabrera hopes the case will spark the federal government to take action in hiring more agents, upgrading equipment and recognizing the dangers Border Patrol agents face every day.

Martinez started in Border Patrol in 2013. He was stationed in Falfurrias for a while before transferring to Big Bend sector to be closer to home.