Investigators found evidence suggesting she may have been abducted. Some of her belongings were found in a field the teen often used as a shortcut to her home, authorities said, and there were signs of a possible struggle.
Businessman and former Moreno Valley City Councilman Mike Rios helped drum up support for a reward.
"We have a 16-year-old daughter ourselves, and it touched our hearts and it touched the way our family is, and we knew we just had to do something, and I didn't see any reward being offered, so I figured that pretty much gets the people to come out and say something," said Rios.
Friends of the family and local business owners have stepped forward to offer a reward. The amount was up to more than $7,500 Monday afternoon.
Even though she has been gone for five days, family members are still holding out hope that the teen will come home soon.
"We just want her home safe, and if you're watching this, please call us. We just need you back home, we're not going to be mad at you or anything," said her sister Sonia Lopez, sobbing at a Friday news conference.
"We just want her back. We haven't been able to sleep, eat or anything, knowing that she's out there, if she's eating, if they're doing any harm to her," said sister Elizabeth Lopez on Monday. "We just want her back."
"You know we love you. We're here for you. If there's a way you could call us, tell us you're safe. We just want you home," Elizabeth said, addressing her missing sister Norma.
Over the weekend, search crews passed out fliers in Moreno Valley. Deputies were assisted by canine units, and more than 200 volunteers helped in the search.
The search has now expanded to Riverside, Redlands and Perris.
"We're trying everything just to get her back safe and sound, to help her return to her own family. We need her back, we want her back, we miss her, we love her," said volunteer Melanie Villarreal.
Authorities said Norma had no apparent problems at home and didn't think she had just run away.
"We do not believe she's a runaway. If we did believe that, we wouldn't be here today," Riverside County Sheriff's Sgt. Joe Borja told reporters at a news conference Friday. "If Norma's out there, we're looking for you. If you haven't been taken, please call. We're worried about you."
Police are also looking for a green SUV that was seen speeding away from the area. Anyone with information related to Norma's disappearance is urged to call Moreno Valley Police at a hotline designated for this case: (877) 242-4345.