Medical examiners have concluded their autopsy of a Border Patrol agent whose death renewed President Trump’s calls for a border wall, but the inquiry could not determine if the agent was murdered or could have died accidentally.

The report released Tuesday evening by the El Paso County Medical Examiner’s Office said Border Patrol Agent Rogelio Martinez, 36, died from blunt injuries to the head, but listed the manner of death as “undetermined.” The coroner made no ruling on the cause of Martinez’s death.

Martinez died Nov. 19, hours after he was found badly injured at the bottom of a roadside culvert 12 miles east of Van Horn, Tex. Another agent, Stephen Garland, was also found injured nearby but survived serious head injuries and other trauma, officials said. Investigators have said he was unable to recall details about the night.

The FBI office in El Paso, about 120 miles from Van Horn, is leading the investigation and has classified the case as a possible assault on a federal officer. FBI spokeswoman Jeanette Harper said Tuesday that the investigation was ongoing but declined further comment.

Although President Trump, Texas Gov. Greg Abbott (R) and other political figures have said Martinez and Garland were attacked, investigators have not said that. Culberson County Sheriff Oscar Carrillo, who was among the first law-enforcement agents to reach Martinez, told The Washington Post the agent’s injuries were consistent with a fall.

Van Horn is more than 30 miles from the Mexican border, but Interstate 10 runs through the town, making it a popular spot for smuggling drugs or undocumented immigrants.

The National Border Patrol Council, the union representing agents, has insisted that Martinez and Garland were attacked, and a spokesman repeated that stance after the release of the autopsy report Tuesday night.

“We believe he was murdered,” union spokesman Chris Cabrera said. “There’s no way he was hit by a vehicle. There’s no way he fell.” 

The autopsy report said Martinez suffered a fractured skull and acute traumatic brain injury. He also had a broken right clavicle and several broken ribs, among other injuries.

Toxicology tests found the barbiturate butalbital in Martinez’s system. The drug is commonly prescribed in combination with acetaminophen and caffeine to treat headaches and other pain.

Nick Miroff in Washington contributed to this report