Plain-clothes border patrol agent kills 32-year-old mother

(CBS News) Residents of Chula Vista, Calif. are angry and confused this week, as police investigate the killing of Valeria Alvarado, a 32-year-old mother of five, by a border patrol agent on Friday. Officials say the agent was trying to save his own life.

Residents of the San Diego suburb, who gathered alongside Alvarado's father and grieving son for a vigil Monday night, claim that that there was no reason for the shooting.

Some details have emerged surrounding the shooting: she was killed by a plain-clothes U.S. border agent, who left her car pockmarked with bullet holes. Authorities say the border patrol agent was in the neighborhood serving a warrant, when Alvarado struck him and he feared his life was at risk as she drove with him on the hood of the car.

Deputy Chief Rodney Scott of the U.S. Border Patrol told CBS News' Bill Whitaker, "He was hit with the vehicle and got lodged on the windshield where you saw the impact and was carried several hundred yards before he discharged his weapon through the windshield of the vehicle."

Witnesses tell conflicting stories of the incident. Ashley Guilebeau, a witness, told Whitaker, "From my apartment, I could see a car stop in the middle of the street and a guy coming and walking in front of the car and shooting about twelve times."

Another witness, Hector Salazar, tells a different story. "The guy was riding on the hood. And then when he was riding on the hood, actually the car stopped in the middle of the road, and I hear the guy yelling 'stop.'"

Border watchdog groups report that Alvarado is the 15th person killed by border agents in the last two years. Christian Ramirez, the director of Southern Borders Community Coalition told Whitaker, "It's very alarming. One death is too much."

"Former FBI assistant director and CBS news senior correspondent John Miller joined "CBS This Morning" to shed some light on the unfolding of events around Alvarado's death.

"What appears happened is there's executing a drug warrant on a location. They have a surveillance team on the perimeter. So far that's all routine," Miller explained. "This car comes out from around the location and someone gets on the radio from the perimeter to the surveillance team and says 'check that car out' ... thinking maybe the suspect is hiding in the back ... So this border patrol agent goes to the car and says 'stop' and that's where the story gets foggy because what we don't know is how did he identify himself ... did he clearly state, 'police' ... what we do know is this thing went horribly wrong."

Miller says the next steps will be to interview the border patrol agent so as to ascertain his state of mind and to compare his account with the account of witnesses at the scene.