It looks like the incident painted as an assault by “illegal aliens” on two border patrol agents near Van Horn, Texas, on Nov. 18 may not have been an assault at all.

A Texas sheriff who was among the first to respond to the scene told the Dallas Morning News Thursday that the incident was an accident, not an assault; he believes a tractor trailer may have accidentally hit Agent Rogelio Martinez, who died, and another unnamed officer, who survived.

“If this was an assault, believe me, as sheriff, I’d be the first one out there emphasizing safety in our community and with our deputies, pairing them up,” Culberson County Sheriff Oscar Carrillo said. “But from what I know and see, that was not the case here.”

But President Trump leaped at the opportunity to blame illegal immigration for the Nov. 18 incident.

“We will seek out and bring to justice those responsible,” Trump tweeted the next day. “We will, and must, build the Wall!”

(In August, Trump defended waiting more than two days to condemn the white supremacists in Charlottesville, explaining that he “wanted to make sure that, unlike most politicians, that what I said was correct. When I make a statement, I like to be correct. I want the facts.”)

The Border Patrol union also jumped on the bandwagon. “What we know is that Border Patrol Agent Rogelio Martinez appears to have been ambushed by a group of illegal aliens whom he was tracking. Our agents’ reports from the ground say that he was struck in the head multiple times with a rock or rocks,” said Brandon Judd, president of the National Border Patrol Council, to the Los Angeles Times.

Sen. Ted Cruz of Texas also called the incident a “reminder of the ongoing threat that an unsecure border poses to our safety.”