Pastrana and her mother, Holly Lynn Codario, disappeared from Ocean City, New Jersey at 11:00 p.m. on January 14, 2003. They were last known to be riding in Codario's mother's black Volkswagen Jetta. At 4:00 a.m. the following day, a toll worker found the Jetta on the southbound shoulder of the Ocean City-Longport Bridge. The car was unlocked and in working condition, with the lights turned off, the keys in the ignition, Codario's purse and driver's license on the passenger's seat, and Pastrana's baby carrier in the back. There were no indications of foul play.

Pastrana's father, Codario's former boyfriend, provided an apartment for them in a gated complex on Delaire Landing Road near State Road in northeast Philadelphia, Pennsylvania. They shared custody of the baby, but Codario was concerned that her boyfriend or his family might try to take Pastrana away from her. She filed for sole custody and child support, but later withdrew both petitions. Codario was exhibiting signs of paranoia at the time of her disappearance. She suspected there were hidden cameras and listening devices in her apartment, and she went to two hospitals and asked them to test her to determine whether she was being poisoned. She may have been suffering from postpartum depression.

Codario's body was found along the south shore of the Great Egg Harbor Bay in the Beesley’s Point section of Upper Township, New Jersey on April 25, 2003. This was two miles directly west of the Ocean City-Longport Bridge. Codario had drowned, and authorities found no evidence of foul play in her death.

Investigators believe Codario probably jumped from the bridge with Pastrana's body in her arms, but there were no witnesses, no note was left behind, and the baby's body has never been recovered.