A body found in a rural field was identified Wednesday as that of a 17-year-old Southern California girl who was likely kidnapped while walking to a friend's home after a summer class.

An autopsy confirmed the identity of Norma Lopez, but investigators would not release the cause of death.

"I don't want to believe it's her," family friend Melanie Villarreal, 18, told The Associated Press. "We know she's in a better place."

Police and the FBI have not identified a suspect and have asked the public for help in the investigation.

"We do have a few leads that we're still following up ... but I wouldn't say that we're any closer," Riverside County sheriff's Sgt. Joseph Borja said.

About 2,000 people gathered around an athletic field at Lopez's school Wednesday evening for a vigil where 16-year-old friend Moises Michel remembered how Lopez loved dance, especially merengue and salsa.

"Whenever we were bored we'd just dance with each other, we'd get up and dance," he said. "I'm used to seeing her every day smiling. I'm just in shock because I can't believe it."

The discovery of the body was reported Tuesday just hours after Lopez's anguished family held a press conference to plead for her return, and authorities said they had no clues and announced a $35,000 reward for information leading to the arrest and conviction of whoever abducted her.

Lopez vanished July 15 after leaving a summer school class at Valley View High School, where she would have been a senior this year. Authorities said she was heading to meet a friend.

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 1 1/2 blocks from the school, and called authorities, Borja said.

The field, a well-known neighborhood shortcut, is off a street that dead-ends at the base of boulder-studded hills cut with trails. Homes line one side, but in the blazing Wednesday heat the expanse of dirt and dry stubble was deserted.

Searchers fruitlessly covered the area for several days.

On Tuesday, a resident driving his tractor-mower on another remote field found the body near a stretch of desert road more than two miles away. The decomposed body, shirtless and clad in jeans, was found face-down in a grove of trees in the agricultural area on the eastern edge of Moreno Valley.

The mix of suburban-style residential sprawl and large rural areas is common in fast-growing Moreno Valley, 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 the killings and is now imprisoned.

"I believe this has been made personal because we all have children," Borja said. "It's probably our worst nightmare that our kids can just be taken from a street and killed."

Borja said it was unknown whether the girl was taken by an acquaintance or a stranger. Her boyfriend had been interviewed several times and was cooperative, Borja said.

He would not provide details on the items found at the site where Lopez was abducted, explaining that releasing further details could hamper the investigation.

"We haven't caught the suspect who killed Norma so obviously there is at least a murderer out there, and so I would be vigilant, I would be aware," he said. "If I was a parent I would keep track of my children. I would do everything I could to ensure their safety."

Valley View High School Principal Kristen Hunter said phone notifications had been made to students' parents urging safety precautions. The school has about 3,000 students, with 400 in summer classes.

Lopez was taking biology over the summer and was doing well in the class, the principal said.

Hunter said teachers described the teen as a very good student and a quiet girl who never got into trouble.

On Wednesday, incoming seniors came and went from campus to have their class pictures taken.

Jennifer Sanchez, 18, said she knew Lopez through a freshman-year club.

Lopez was sweet and quiet and mostly spent time at school with her older sister, who graduated last year, her younger sister, and her on-and-off boyfriend, Sanchez said.

"We called them 'the Lopez sisters' because they were really close to each other," Michel said. "They spent a lot of time together."

(This version CORRECTS A new approach. Updates with details, community vigil, quotes, scene, area description. Corrects that she was walking to a friend's home, not her home. AP Video.)