Denial of Bail for Border Agent Sought : Killing: Prosecutor bases argument on seriousness of crime. A relative of the victim says shots came without warning.

A U.S. Border Patrol agent charged with first-degree murder in the shooting of a Mexican citizen dragged the victim’s body 30 yards in an effort to conceal the remains, a prosecutor said Friday.

Also Friday, a relative who accompanied the victim the day of the shooting said in an interview that two agents opened fire with high-powered rifles without warning and without identifying themselves and continued to fire as the men fled back toward Mexico.

The prosecutor, Jose Luis Machado, attorney for Santa Cruz County, argued Friday that agent Michael Andrew Elmer should be denied bail because of the gravity of the alleged crime, for which Elmer could face the death penalty.

Elmer, the first Border Patrol agent in memory to be charged with murder during performance of his duties, has been in custody since June 13, when he was arrested in the slaying of Dario Mirando Valenzuela, 26, from Nogales, Mexico. Valenzuela was killed the evening of June 12 in an isolated canyon west of here, just north of the international line.

Five Border Patrol officers, including Elmer, were in the vicinity at the time of the killing, but all say they did not see the shooting, authorities say. Prosecutors say they are investigating the possibility of a cover-up in the case.

Elmer, a native of New Mexico who was reared in small-town Arizona, is an avid outdoorsman and the divorced father of two. He enlisted in the Army as a senior in high school and served for seven years before joining the Border Patrol. He served in the Gulf War as a National Guard member.

The shooting occurred in an area frequented by illegal immigrants and drug smugglers, officials say. The five agents were assigned to conduct surveillance of narcotics trafficking routes at the time of the incident.

Authorities say no evidence of drugs was found at the scene. Friends and relatives say Valenzuela, a father of two, was en route to a construction job in Tucson.

Eduardo Torres Berber, 23, who accompanied Valenzuela on the trip north, provided an account of the evening in an interview Friday. He said Valenzuela, his brother-in-law, chose to hike a circuitous route through remote canyons to avoid immigration officers.

Torres said he was walking about 15 yards in front of Valenzuela, heading north, when he heard a shot and saw an explosion of dirt at his feet. Torres said he looked up and saw a man dressed in a military-style uniform holding a long rifle and threatening in broken Spanish to kill him.

Torres said he turned and ran as fast as he could as at least 20 bullets smacked into the ground. Torres said he heard a separate volley of shots nearby that he presumes were aimed at his brother-in-law.

Daring a glance back, Torres said Friday, he saw the silhouettes of two people armed with rifles on a small hilltop. He said he returned to Mexico and learned from news accounts that Valenzuela was dead.

“There was no warning. They just fired,” said Torres, interviewed on the steps of a church in Nogales, Mexico, where a funeral Mass was held Friday.