She was beaten to death with a hammer, then burned beyond recognition. It's the first murder in Aurora in more than a year.

She was a hardworking teenager and loving family member, who wanted to become a police officer, former co-workers and relatives said Monday.

So when Abigail Villalpando didn't show up for her waitressing job Thursday, family members called authorities. They later learned that the West Aurora High School senior had been struck repeatedly with a hammer, her body doused with gasoline and set ablaze in a barrel in the backyard of an Aurora home. Her car was torched and left at another location.

The teen's remains were so badly burned that officials had to use dental records to identify her, authorities said.

Police charged three men in Villalpando's slaying, one for her death and two for concealing her homicide. Police said the victim knew the man charged with her death, but authorities did not disclose a motive in court. It was the first slaying in Aurora in more than a year.

The victim's brother, Ricardo "Ricky" Villalpando, 21, said he and his sister moved into an apartment together in September. Abby, as she liked to be called, wanted to be a police officer because of her love of children, and she planned to go to college after her summer graduation, he said.

"My sister was the most responsible 18-year-old I knew," said Villalpando, the oldest of four. "Everything she had — her car, her insurance, her clothes — she paid for on her own."

Ricky Villalpando described the suspects as his sister's best friends. They met in middle school, Villalpando said.

He said Juan Garnica Jr., the man charged with the slaying, was jealous that she was seeing someone else and was "obsessed with her."

Police have not talked about a motive.

The killing of Villalpando, who worked at Denny's, shocked those who respected her for her work ethic and buoyant personality.

Her sweet demeanor — which kept regulars coming back to the restaurant where she worked after school — made it almost impossible for those who knew her to comprehend her death.

"They can't understand why something like this would happen," said Ben Richter, manager at the restaurant where Villalpando worked for three years and where shocked customers called to express condolences. "She will be missed."

Garnica, 18, of Aurora, was ordered held on $5 million bail for beating Villalpando to death with a hammer Thursday, authorities said.

The two men charged with concealing the homicide are Enrique Prado, 19, and Jose Becerra, 20.

Villalpando was a caring person who had told family members she was trying to make some personal changes, said a friend of the family, Jose Ocampo.

"She was trying to change her life around," he said.

Villalpando transferred in mid-December from East Aurora High School, according to Mike Chapin, community relations director for School District 129.

Students at the high school were alerted of Villalpando's death in a morning announcement.

School officials spent the weekend preparing teachers and a crisis team of social workers and psychologists to help the 3,500-student population to cope, Chapin said.

"As long as any student needs assistance working through this, there will be resources," Chapin said. "It's a horrible thing for the students to even try to comprehend."