Los Angeles, California (CNN) -- A sister of a 17-year-old girl whose body was found this week two miles from her home in southern California said Friday she would not rest until the killer is apprehended. "I will not have peace until this this person is found," Elizabeth Lopez, 18, said about the killer of her younger sister Norma, who vanished last Thursday as she walked home from summer classes at Valley View High School in Moreno Valley, about 70 miles east of Los Angeles. Authorities believe that Norma, who had planned to meet a younger sister and a friend at home, took a short cut through a dirt field to reach the family's residence. Her sister contacted the police when Lopez failed to return home. The girl's body was discovered Tuesday two miles away and identified Wednesday through dental records, police said. "I always thought it was something safe," Lopez said about the path her sister typically followed. "I never suspected that my sister would get kidnapped in this empty lot of just dirt." Sgt. Joe Barja of the Riverside Valley Sheriff's Department declined to reveal the cause of death or reveal any injuries Lopez may have sustained but said the department is treating the death as a homicide. The victim's sister said the family was trying to stay strong and to find the killer. "That's what's keeping us motivated -- to get that person in custody so no other family could actually go through what we are going through," Elizabeth Lopez told HLN's "Prime." "There's a family here that loved her very much, even though sometimes we did fight -- but it was something stupid, something dumb. But we love her and miss her and one day we will be together again." She expressed gratitude for the outpouring of support the family has received from the community, including a memorial service at the high school, which hundreds of students attended. "I get a lot of strength from this," she said. "I did not expect this many people to actually support us. I thought this was just going to be one of those kidnappings that people don't really get involved with ... I did not really expect anyone to actually really listen to the story that we had." Lopez said her sister had hope to become a fashion designer, a makeup artist or a model. "She had really big dreams in life," she said. She recalled the last time she saw her sister, the morning of her disappearance. "She brought me a peanut butter and jelly sandwich and I opened up my sandwich and it had a happy face made with banana in it," Lopez said. The offering was intended to to persuade her sister to lend her a pair of shoes, she said. Police are looking for a green "SUV-type vehicle" that was seen driving from the area at the time of Lopez's disappearance. 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. The victim's father, Martin Lopez, 44, told CNN in a telephone interview that the neighborhood was generally a safe one and that Norma usually took precautions to stay safe. "She never walked around without her mother," he said in Spanish. CNN's Tom Watkins contributed to this report.
Sister "will not have peace until this person is found" Norma Lopez's body was discovered Tuesday . Norma dreamed of being a fashion designer, makeup artist or model . Authorities believe teen was taking a shortcut home when abducted .