VAN HORN — Nearly two weeks after a U.S. Border Patrol agent died near here, investigators are exploring whether an accident, not an attack, is the cause of his death.

Evidence gathered at the scene does not suggest an assault, multiple sources with direct knowledge of the investigation say. The possibility that Rogelio Martinez and his partner were sideswiped by a tractor trailer’s side mirror on a moonless night is growing theory, they said, speaking on the condition of anonymity.

When asked specifically about the possibility of an accident, FBI spokeswoman Jeanette Harper confirmed Wednesday that investigators are exploring that scenario, but she said they had not ruled out an attack by immigrants or drug traffickers, or other scenarios.

“We’re looking at everything,” Harper said, adding it will be weeks, if not months before the investigation is completed. “We’re doing our due diligence throughout the course of the investigation. The FBI role is to determine the facts in this tragic incident.”

Immediately after the death of Martinez on Nov. 18, the National Border Patrol Council insisted he and and his partner were stoned by undocumented immigrants, drug traffickers or both. President Trump tweeted "... we will, and must build the Wall."

Culberson County Sheriff Oscar Carrillo, one of the first responders on the scene, believes a tractor trailer could have accidentally sideswiped Martinez and his partner while they were standing near a culvert just feet from Interstate 10. The highway is a heavily traveled route for interstate truckers and there have been a number of accidents, some of them caused by wind drafts, or drivers overcorrecting on the lonely road, Carrillo said.

“From the beginning we were radioed to assist in the incident as an injury, not an assault," he said. "That’s the way it was communicated to us.

“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,” he added. “But from what I know and see, that was not the case here.”

Union officials insisted their own review is accurate, citing unspecified on-the-ground information. They have insisted Martinez’s death underscores the need for more manpower and resources to secure the border.

Rogelio Martinez (FBI)

“The injuries to Martinez could not have happened the way the media has been trying to portray,” said Stuart Harris, vice president of the Border Patrol Council Local 1929. “Agent Martinez was ultimately murdered. The agents were tracking footprints and were ultimately ambushed, and assaulted by, I don’t know who, but it could have been illegal immigrants or drug traffickers.”

When asked Wednesday about the possibility of an accident, Harris said, “The injuries sustained by agent Martinez were far more severe than what would have been caused by an accident. Are we supposed to believe the same accident happened to both of them?”

Martinez and his partner suffered severe head injuries. The second agent managed to call his wife for assistance, but claims memory loss.

Harris said that he talked to the agent this week, but would not describe the conversation. Asked whether the agent suffered from memory loss, Harris said, “That’s all been reported, and I will not get into that.”

The FBI is publicizing a $25,000 reward on digital billboards along I-10 and Interstate 8 from Southern California to Texas seeking information about Martinez’s death.

A full autopsy may not be known for weeks, said Annabel Salazar, chief investigator at the El Paso medical examiner’s office. She said preliminary results show that Martinez died of head injuries.

Special Agent in Charge Emmerson Buie Jr. said during a news conference last week in El Paso that authorities are investigating the death as a “potential assault,” but he wouldn’t rule out that they could have been hurt in some other way.

Asked last week about Trump’s comments, he said, “I have not briefed the president.”

The “rush to judgment” has made law enforcement officials’ work more difficult, Carrillo said.

“We owe it to the young agent and his family to conduct a slow and meticulous investigation,” Carrillo said.

Carrillo is confident federal investigators will get to the bottom of the mystery. He’s eager to see the full autopsy report. “Just because you die doesn’t mean all is lost. The body can tell a story.”

The death of Martinez, an El Paso native and fellow alumnus of Irvin High School on the city’s northeast side, hit close to home.

“This could have been me,” Carrillo said. Taking a long pause, he added, "The problem today is that it's hard to sell anything, especially the truth."