Jonathan was last seen in Miami, Florida on August 28, 1999. He disappeared with his brother, Mario Mordoche, and their mother, Yakelin Llanes. Llanes planned to drive to Tampa, Florida to visit her ex-boyfriend, Jonathan and Mario's father. They were traveling in a rented brown 1999 Chevrolet Malibu with the Florida license plate number GH830M. Llanes told her family her ex-boyfriend was going to give her a new car and she would return driving that. They never arrived at his home and have never been heard from again.

It's unclear whether the family actually embarked on their planned trip to Tampa; there was no evidence in their apartment of any preparations for the trip, and Llanes's toothbrush was left behind. Their cases remain unsolved.