Authorities credited investigative work that led to the arrests. The victim's grandmother, Kim Kirby, said she collapsed when she was informed of the arrests.
"My son had to hold me, and just thinking, 'Oh my God, we did it. We did it. We found him,'" she said. "I can't believe that they were going to try to live their life and act like nothing happened.
Carlos Parra, 20, and Rebecca Beltran, 24, both from Santa Ana, were arrested early Wednesday morning at their Anaheim apartment. Parra was booked into Orange County Jail for felony hit-and-run, and Beltran was booked for accessory to a felony.
Miranda Palacios was crossing Gilbert Street with her mother when they were struck by a driver of a 1995 beige Nissan Maxima on Feb. 8. Palacios died at the hospital, while the girl's mother, Augi Hernandez, suffered several broken bones and continues to recover.
Investigators said Parra was driving his sister's Maxima when he hit the girl and her mother. He didn't stop or pull over to help, and later ditched the car. He then called his girlfriend, Beltran, who is accused of aiding in the felony hit-and-run.
"It is our belief that after the collision occurred and he fled the scene, he called her, and she then reported the car stolen.
Kirby said she can't understand how the driver could keep going after hitting her granddaughter.
"How could you leave my grandbaby face down in a gutter, bleeding to death," she said. "Why didn't you stop?"
Beltran has bailed out of jail. Parra is being held without bail.