Slain California teen's sister urges unknown killer to surrender and asks: 'Why her?'

and even after her abduction and murder, she left those closest to her with a smile.

The morning Lopez, 17, was kidnapped, she fixed her older sister a peanut butter-and-jelly sandwich for lunch in exchange for borrowing a pair of black flats. Inside the bread, her sister found a goofy smiley face of banana slices.

"She just came barging in and said, 'I need your shoes' and left. That's the last time I saw my sister," Elizabeth Lopez said, tears in her eyes. "Her room is empty. There's no Norma."

Four of the raven-haired teen's six siblings gathered outside the family home Thursday to remember Lopez and to plead with her killer to surrender and to explain why the teen was targeted in the middle of the morning just blocks from her school.

Lopez, an avid dancer and aspiring fashion designer, was last seen July 15 at Valley View High School, where she was taking a summer biology class. She was abducted while walking to meet a friend after class and her decomposed body was found five days later — wearing pants but no blouse — in a field less than three miles away.

"The person that did this, why? Why her?" her older sister said. "I don't want anybody to go through this, but why her? She had never done anything to anyone."

Their father, Martin Lopez, said he believed he felt it in his heart when his daughter died.

"For me, the way I felt it, you feel it in the chest like a pressure, like a hit, like someone was hitting me," he said in Spanish.

Investigators conducted vehicle checkpoints Thursday and questioned sex offenders as the hunt for the killer expanded.

Authorities questioned drivers on a street outside the school, which is near the site where Norma Lopez's belongings were found last week. Detectives hoped to find someone who saw the girl close to the time she was abducted.

Fourteen registered sex offenders live within a two-mile radius of the high school where Lopez was last seen, according to the Megan's Law website.

Lopez's sister, Elizabeth Lopez, said the teen disappeared while she was going to meet her younger sister at a friend's nearby home, as she had done every day after class since summer school began.

When she didn't show up, her younger sister and a friend went to look for her, found some of her personal items in a field 1½ blocks from the school and called authorities, said Sgt. Joseph Borja, spokesman for the Riverside County Sheriff's Department.

The field, a well-known neighborhood shortcut, is off a street that dead-ends at the base of boulder-studded hills cut with trails and Norma Lopez cut across it often, her family said.

Searchers fruitlessly covered the area for several days before her body was discovered Tuesday by a man clearing brush in another rural field more than two miles away.

Police want to speak with the driver of a green SUV seen speeding from the area the day Norma Lopez vanished.

Authorities have declined to release her cause of death, citing the ongoing investigation, and would not say if she was sexually assaulted. Her body was identified using dental records.

Her father said Thursday that investigators also took blood samples from Norma Lopez's sisters and mother and took hairs from her brush as part of the investigation. He said he did not know if she had been sexually assaulted.

The parents, who are originally from Guanajuato, Mexico, were being assisted by the Mexican consulate, said Carolina Zaragoza, head of the consulate's local office.

Moreno Valley is a city of 186,000 about 60 miles east of Los Angeles, between March Air Reserve Base and a swath of unforgiving, rugged terrain known as The Badlands.

The teen's disappearance drew wide attention across Southern California, where the high-profile abduction-murders of two other teenage girls in San Diego County — one jogging alone this year and the other walking to school in 2009 — led to a sex offender who ultimately admitted to the killings and is now imprisoned.

Norma Lopez and her two oldest sisters were a year apart and were so inseparable they were nicknamed the "Lopez triplets."

The teen loved to dance and would often choreograph salsa and meringue routines for the Latin American cultural club with younger sister Sonia Lopez.

She planned to study to become a makeup artist after graduating next year — but also spoke of becoming a fashion designer, a dancer or a model, said her older sister, Elizabeth Lopez.

"My heart's broken to pieces," she said. "When she saw me graduate, she said, 'That's going to be me next year.' She was the biggest everything in the family. She wanted to be famous, to be a star."