Probe Fails to Prove Border Agents Crossed Into Mexico : Immigration: Investigators say the fence the agents may have passed to make an arrest is slightly north of border. The two officers are back on regular duty.

Two U.S. Border Patrol agents are back on regular duty after federal investigators failed to substantiate widely publicized reports that the two officers crossed onto Mexican soil while making an arrest almost two months ago, authorities said Tuesday.

Gustavo de la Vina, chief agent of the U.S. Border Patrol in San Diego, said an internal investigation “did not substantiate any misconduct on the part of the agents.”

Although not disputing that the agents may have wandered south of the border fence, De la Vina noted that the fence does not precisely delineate the international border, but only approximates it. The actual boundary line is, at certain locations, several yards south of the tattered fence, he noted.

“The investigation could not conclusively establish that the officers entered Mexico,” De la Vina said.

The two agents, who were not identified, had been transferred to desk assignments pending the outcome of the inquiry.

The Border Patrol’s decision would appear to close the book on an incident that had pitted Border Patrol’s union against management in an unusually acrimonious public dispute. The incident also had touched a raw nerve in Mexico, where any allegations of U.S. operations south of the border inevitably inflame nationalistic passions.

Moreover, it had occurred only 15 days after a plainclothes Border Patrol agent shot and killed a 17-year-old Mexican man along the border fence in San Diego in an incident that several Mexican witnesses have described as an unprovoked point-blank execution. The Border Patrol says the agent fired in self-defense in the midst of an attack by the suspect.

Official Border Patrol policy prohibits agents from entering Mexican territory. Although the fence is not a precise boundary marker, officials say agents are instructed to act as though it is and to avoid going south of the fence except in extraordinary circumstances--such as coming to the assistance of an injured person or crime victim. “Normally, we are not going to work south of that fence,” said Robert Gilson, assistant chief Border Patrol agent.

There were no known injuries in the incident involving the two agents who purportedly crossed the border into Mexico. The incident occurred Sept. 23.

An amateur photographer snapped images indicating that the officers had crossed to the south side of the border fence on foot while attempting to arrest an unidentified man. One of the photographs appeared on the front page of the San Diego Union.

Initially, the Border Patrol stated that a “preliminary investigation” had found that the agents “were a few feet south of the border.”

However, the National Border Patrol Council, the Washington-based union representing border officers, embarked on a spirited public campaign on behalf of the two agents. The union maintained that the border fence was actually “several yards north” of the actual international boundary line, and accused Border Patrol management of reassigning the agents “for purely political reasons.”

Patricia Nighswander, executive director of the National Border Patrol Council, said Tuesday that she had not been informed of the agency’s decision.