Taking to the streets after hearing a loud crash on Halloween night, Brenda Gonzalez soon saw signs of her sister: the pillowcases she and her friends had been carrying for candy, the tutu she'd been wearing.

"The first thing that came through my mind was, why isn't anybody helping them," Gonzalez, 24, said Monday. "A few seconds later I realized, you know, there's a reason they're not helping them. They're gone."

Gonzalez's sister Andrea Gonzalez was among the three 13-year-old trick-or-treaters hit and killed by an SUV as they crossed the street. Her friends, twin sisters Lexi and Lexandra Perez, were also killed.

Gonzalez said Andrea, who loved music and baking, decided not to go to a Halloween party this year so she could trick-or-treat with her loved ones.

"She was so selfless. She never asked for anything," Gonzalez said, wiping away tears at a makeshift memorial marked by dozens of balloons, flowers, candles and photos. "She didn't even want to ask my mom for a costume for Halloween."

The California driver who police say struck and killed the teens before fleeing had recently pleaded guilty to a separate hit-and-run, authorities said Monday.

Jaquinn Bell, 31, of Orange, drove a black Honda SUV through a marked crosswalk Friday near an elementary school in Santa Ana, police said.

The victims, wearing costumes, were found lying in the street.

Authorities believe Bell fled with his two teenage children after ditching the damaged car in a nearby parking lot. He was arrested Sunday at a motel in Stanton, said Santa Ana police Chief Carlos Rojas.

"He left. He did not try to render aid, and thank God for other witnesses there who contacted the police department and allowed us to respond rather quickly," Rojas said. "Unfortunately it was a tragic end."

It was unclear why the driver fled the scene.

Trick-or-treaters were also injured and killed in collisions in New York, Florida, Washington state and the nearby Orange County, California, city of Irvine, where 65-year-old John Alcorn died after he was struck by a car. His 4-year-old son was in critical but stable condition.

In Santa Ana, Bell was arrested for investigation of felony hit-and-run causing death and was being held on $500,000 bail. The case has been referred to the district attorney for possible charges. It was unclear if Bell has an attorney.

Online court records show Bell pleaded guilty in August to misdemeanor counts of child abuse, driving under the influence and hit-and-run with property damage. He was sentenced to 10 days in jail, three years' probation, and alcohol and child abuse treatment programs, according to a court spokeswoman.

He has prior convictions for reckless driving, spousal injury and violation of a protective order, the records show.

Santa Ana police Cpl. Anthony Bertagna said Bell also had two outstanding bench warrants for $30,000 as of Monday. Further details on the warrants were not immediately available.