The agency’s original statement said the officer was searching for “illegal activity” in a culvert on a residential street in Rio Bravo, a border town about seven miles south of Laredo, when a group of undocumented immigrants started to hit him with “blunt objects.”
An updated statement, sent on Friday, said that the officer, a 15-year veteran of the Border Patrol, ordered the immigrants “to get on the ground” but “the group ignored his verbal commands and instead rushed him.”
The new statement also used different language to describe the woman now identified as Ms. Gómez.
The earlier statement said that the officer, whose name was not released, fired at least one shot with his handgun, “fatally wounding one of the assailants.” The updated statement did not refer to her as an “assailant,” saying instead that the officer fired one round, “striking one member of the group.”
The Border Patrol agent was put on administrative leave, and the F.B.I. and Texas Rangers are investigating the shooting.
Marta V. Martinez, who lives on Centeno Lane, next to the site of the shooting, on Thursday disputed Customs and Border Protection’s first account of the shooting, saying she didn’t see any weapons the group could have used.
“There was no weapon. They were hiding,” Ms. Martinez said of the undocumented immigrants, adding that she “didn’t hear any yelling or ‘stop’ or ‘don’t run.’”
After hearing the gunshot, she ran outside, saw Border Patrol agents on her block and hit record on her cellphone. She then peered over a chain-link fence to the adjacent lot, she said, and saw an officer flip over a woman’s body.
The officer began doing chest compressions on the woman, but Ms. Martinez said it was clear that the woman had already died.