Mario Lopez was 6 years old when he vanished from Livingston, California. He was last seen on March 8, 2005, playing basketball at Livingston Middle School with his 12-year-old foster brother, Joel, around 5:30 p.m. Their foster parents reported both boys missing about two hours later.

Neither child took extra clothing or belongings and neither had a history of running away, which made the disappearance especially worrying. Authorities at the time suspected the boys might have been taken by their biological parents, though that was not confirmed; there was also speculation they could be somewhere locally or may have traveled to Fresno. Joel was later found, but Mario remains missing and is classified as endangered missing.

Anyone who has information that could help locate Mario is urged to come forward.