PROVO — An Amber Alert issued for a 13-year-old Provo boy was canceled after about 12 hours Saturday when police said they believed the teen was no longer in danger.

The alert was issued just after midnight by Provo police who said Pablo Enrique Rivera's biological father, who has no legal custody of him, had taken him and was headed to Mexico.

About 12 hours later, police sent a message on Twitter, saying: "We believe Pablo is in Mexico and is not in any danger." A later tweet said, "Not in imminent danger."

About 8 p.m. Friday, Maria Hernandez came home to discover that her son was missing. Police said her son had left a note saying he wanted to go to Mexico with his father, Juan Enrique Rivera Casillas.

The two likely left Provo about 2 p.m. and traveled with the boy's grandfather, said Provo Police Lt. Mathew Siufanua. A "ping" from the boy's cellphone was detected near Barstow, Calif., about 10:30 p.m. Friday.

Detectives were working with border patrol agents to try and prevent them from entering Mexico, likely to Guadalajara. But the alert was canceled once police determined that the boy was likely already in Mexico. The case will now be a matter for the courts, Siufanua said.

Police say five years ago, the father did the same thing with an older sibling.