The girl was taken into protective custody and San Bernardino County sheriff's officials were en route to Las Vegas to conduct interviews.
The sheriff's department said Miranda Hemphill was last seen Sunday around 2 a.m. near her home. Her parents reported her missing to Victorville police later that morning. An Amber Alert was issued on Tuesday.
Authorities believe she ran off with Lopez, who is from Lennox. Upon investigation, authorities found that Lopez currently has an active felony warrant in San Bernardino County for a sex crime involving a minor that occurred in 2009.
Hemphill met Lopez online in May. He told her and her friends that he was 17 years old. The two dated off and on for months until Hemphill eventually broke things off. However, Lopez talked her into running away with him and the two took off to Vegas.
Hemphill's father posted a video message on YouTube, pleading for his daughter's return.
"All of your friends and family are worried sick about you. You are amazing. You are everything to us. We all love you and we all care about you. Please, just turn around and come home," said Hemphill's father in the video.
Her family credits authorities for finding her along with tips from the public.
"She's my baby sister, and I'm so glad that everybody helped to bring her to us. Thank you guys for using the YouTube video to get the ball rolling. For the first 24 hours, we almost lost her, and the last 24 hours helped us find her," said Hemphill's sister, Jennifer Stolpp.
"I was very positive, and I had a feeling that she was going to be OK," said the victim's father, Robert Hemphill.
If you have any information regarding this incident, you're asked to contact the San Bernardino County Sheriff's Department at 1-866-346-7632.