THE LATEST on the death in Texas of a U.S. Customs and Border Protection agent (all times local):

4:10 p.m.
A union official says a U.S. border agent who died while on patrol in West Texas appears to have been struck in the head with a rock or rocks.
Chris Cabrera, a spokesman for the National Border Patrol Council, said Monday that U.S. Customs and Border Protection agents who responded to the scene Sunday described it as “grisly” and said the dead agent, 36-year-old Rogelio Martinez, and his partner had “extensive injuries.”
A Border Patrol spokesman said Martinez died at a hospital and that his partner, whose name hasn’t been released, was seriously injured.
It has been more than 24 hours, yet there hasn’t been an official explanation of what happened. Several elected officials have said the agents were attacked, including President Donald Trump, who renewed his call for a border wall between the U.S. and Mexico.
The incident or attack happened near Van Horn, which is about 30 miles (48 kilometers) from the Mexico border and about 110 miles (177 kilometers) southeast of El Paso.
___

12:45 p.m.
Texas is offering a $20,000 reward for information that leads to the arrest and conviction of the person or people who killed a U.S. border agent and injured another.
Gov. Greg Abbott announced the reward in a statement Monday in which he expressed gratitude to U.S. Customs and Border Protection agents.
Agent Rogelio Martinez was killed and his partner was seriously injured Sunday in what elected officials have said was an attack near Van Horn, which is about 30 miles (48 kilometers) from the Mexico border and about 110 miles (177 kilometers) southeast of El Paso. Martinez’s partner, whose name hasn’t been released, is hospitalized in serious condition.
Investigators haven’t released certain details about the case, including what time it happened and whether they’re pursuing specific suspects. An FBI spokeswoman did say the agents were not shot.
___
11:45 a.m.
President Donald Trump has offered condolences to the family of a Border Patrol who was killed in an apparent attack in West Texas.
Trump says a second officer injured Sunday was “brutally beaten and badly, badly hurt” but “looks like he’ll make it.”
The president spoke at a Cabinet meeting Monday at the White House. He says the wall he has promised to build along the border between the U.S. and Mexico is on the agenda.
Trump says the wall is necessary because “it’s rough territory” down there and a lot of things are happening along the border, including drug trafficking. He pledged that “we’re going to straighten it out.”
The Border Patrol has released few details about what led to the death of 36-year-old Agent Rogelio Martinez, including whether investigators have any suspects or think smugglers or people who were in the country illegally were involved.
https://twitter.com/realDonaldTrump/status/932420488642617344
___

10:30 a.m.
Authorities were scouring West Texas on Monday for those behind an apparent attack that killed one U.S. border agent and injured another.
U.S. Customs and Border Protection issued a statement Sunday that was thin on details about what happened, saying the two agents “were responding to activity” while on patrol near Interstate 10 in the area of Van Horn, which is about 30 miles (48 kilometers) from the border with Mexico and about 110 miles (175 kilometers) southeast of El Paso.
CBP spokesman Douglas Mosier said 36-year-old agent Rogelio Martinez and his partner were transported to a hospital, where Martinez died. Martinez’s partner, whose name hasn’t been released, is in serious condition.
Elected officials referred to it as an attack, with President Donald Trump tweeting Sunday night that “We will seek out and bring to justice those responsible.” He also reiterated his call for a border wall with Mexico.
Texas Gov. Greg Abbott tweeted that it was an attack. And Republican Sen. Ted Cruz also referred to it as such, saying in a news release: “We are grateful for the courage and sacrifice of our border agents who have dedicated their lives to keeping us safe.”
Kevin McAleenan, acting commissioner of CBP, said in a letter sent to border agents that Martinez was unconscious when agents found him, with “multiple injuries” to his head and body.
Jeanette Harper, FBI spokeswoman for the El Paso field office, told the San Antonio Express-News only that Martinez and his partner were “not fired upon.” The FBI has taken over the investigation.
Border Patrol records show that the agency’s Big Bend sector, which includes the area where Sunday’s attack took place, accounted for about 1 percent of the more than 61,000 apprehensions its agents made along the Southwest border between October 2016 and May 2017. The region’s mountains make it a difficult area for people to cross illegally into the U.S. from Mexico.
The Border Patrol website lists 38 agents, not including Martinez, who have died since late 2003 — some attacked while working along the border and others killed in traffic accidents. Martinez is the second agent to have died this year.
____
8:50 a.m.
Texas Gov. Greg Abbott and Sen. Ted Cruz have characterized it as an attack that caused the weekend death of a border agent and injuring of a second.
The Republican senator said in a statement Sunday that 36-year-old Agent Rogelio Martinez died as a result of the attack earlier that day near Van Horn, which is about 30 miles from the Mexico border and 110 miles southeast of El Paso. He said the nation is grateful “for the courage and sacrifice of our border agents.”
Abbott also described the incident as an attack in a tweet Sunday.
The Border Patrol hasn’t released many details about what happened. It said in a statement that the agents “were responding to activity” while on patrol near Interstate 10.
The FBI has taken over the investigation.
___
The FBI is investigating, after a U.S. Customs and Border Protection agent was fatally injured responding to activity along the Mexico-Texas border.
A Border Patrol spokesmen said the agency could not provide any details Sunday on what caused the agent’s injuries or what led to them.
Another spokesman, Douglas Mosier, said Agent Rogelio Martinez, 36, and his partner were transported to a local hospital, where Martinez died. Martinez’s partner is in serious condition. His name wasn’t released. Martinez had been a border agent since August 2013 and was from El Paso.
President Donald Trump commented about the incident on Twitter Sunday night amid a series of unrelated tweets.

Texas Governor Greg Abbott and Texas Senator Ted Cruz also tweeted, after the incident:


Cruz added, in the tweet:
"This is a stark reminder of the ongoing threat that an unsecure border poses to the safety of our communities and those charged with defending them. We are grateful for the courage and sacrifice of our border agents who have dedicated their lives to keeping us safe. I remain fully committed to working with the Border Patrol to provide them with all the resources they need to safeguard our nation."
In an online statement, U.S. Customs and Border Protection (CBP) said:
A U.S. Border Patrol agent died this morning as a result of injuries sustained while on patrol in the Big Bend Sector.
Agent Rogelio Martinez and his Big Bend Sector partner were responding to activity while on patrol near Interstate 10, in the Van Horn Station area. 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.
Border Patrol agents from Big Bend Sector and the Culberson County Sheriff's Department secured the scene. The Border Patrol's Special Operations Group and agents from CBP's Air and Marine Operations are searching the area for potential suspects or witnesses.
The Culberson County Sheriff's Department, Federal Bureau of Investigation, Office of Inspector General, and CBP's Office of Professional Responsibility are investigating.
Our thoughts and prayers are with Agent Martinez and his family, and with the agent who was injured.
According the CBP’s website, The Van Horn Station area of responsibility consists of 15 miles of border with Mexico; and it is a part of The Big Bend sector. The Big Bend Sector covers over 135,000 square miles, encompassing over 118 counties in Texas and Oklahoma.
The Border Patrol website lists 38 agents who have died since late 2003 — some attacked while working along the border and others killed in traffic accidents. It lists one other agent death in the line of duty this year.