ILOILO CITY, Nov. 21 -- Authorities say there is still no concrete evidence linking the 15-year-old public high school student to the series of bomb threats in the city, even as the minor was taken into custody on Thursday evening after a classmate reported seeing him copy the threats being sent to other schools before forwarding one to his own school, Fort San Pedro National High School.

"Initially, based on the latest investigation, it could not be established that it was coordinated with other threat messages that were sent to other schools," Iloilo City Police Office (ICPO) spokesperson Maj. Shella Mae Sangrines said in an interview on Friday.

The minor was released to his family on Thursday evening, but will have to undergo process...