[atomicpossum]

Authorities said Martinez was on the Mexican side of the border at the time, but may have picked up rocks and made motions as if to throw them at the U.S. agent.

Brought rocks to a gunfight.

[theDentist]

I bet he was more likely firing a weapon (or about to). Rocks aren't likely to draw live fire. When he was hit, his friends left him and took the gun.

[DumpsterDiver]

Authorities said Martinez was on the Mexican side of the border at the time, but may have picked up rocks and made motions as if to throw them at the U.S. agent.

This article states:

Raul Martinez, a spokesman for the U.S. Border Patrol in San Diego, confirmed that an agent had fired on a man on Friday as he tried to cross the border near San Diego, after the would-be immigrant had thrown rocks at him.

The unidentified man crossed back into Mexico, where he later died of his injuries in a hospital.

"The Mexican government is demanding an investigation of the facts," presidential spokesman Ruben Aguilar said at a news conference.