Police, family baffled by siblings' deaths - The fatal shootings of a brother and sister at a South L.A. party appear random, officials say.

Beatriz Santiago, 21, who was about to start her senior year at UC Riverside and poised to be the first in her family to graduate from college, was in the backyard dancing. Her brother Roberto, 22, was sitting on the back porch of a house in the 1400 block of West 38th Street, where the party was held.

About 2:30 a.m. Sunday, a spray of shots blasted from the alley on the other side of the backyard fence. Three people were hit. Beatriz and Roberto Santiago died of their wounds.

Los Angeles Police Department detectives say they are baffled. They describe the Santiago siblings as having no gang ties -- though the neighborhood is known for gang violence.

Police believe the assailants fired randomly into the party. The shooter couldn't see the specific targets, said LAPD Cmdr. Pat Gannon, head of the South Bureau homicide unit.

"They were just shooting into a backyard where they knew a lot of people were standing. The shooter hit the brother and sister by chance. They weren't near each other," Gannon said.

Elizabeth Santiago, 26, eldest of the five Santiago children, said her family had spent the last few nights dealing with the loss and trying to understand why it happened.

"I wake up at 4 a.m. and I hear my dad crying, asking God, 'Why did this happen to my family?' " she said. "We just can't comprehend how out of everyone that was there, they were the two that got killed. It's unjust; they didn't deserve that. My brother doesn't belong to a gang. [My parents are] just in shock. Losing one would have been enough, but two."

The Santiagos moved to Los Angeles about three decades ago from Oaxaca, Mexico, and after years of living in cramped apartments were able to buy their first home 16 years ago.

Roberto Santiago Jr., the family's only male child, had recently been working with his father at a restaurant in Beverly Hills. The younger Santiago was also attending community college classes at night.

But the family's measure of success in the United States had little to do with buying a home or being able to pay bills. The true symbol of "making it" as an immigrant family was carried by Beatriz, the middle child, Elizabeth Santiago said. In one more year she would finish at UC Riverside. She talked of pursuing a career in social work and giving something back to the community.