ANNANDALE, Va. (CBSDC) — Fairfax County Police arrested 19-year-old Marco Antonio Verduo Toledo in connection with a bomb threat at Annandale High School that delayed classes for hours and disrupted bus service for many other students across the county Friday morning.

Police were called to 4700 Medford Drive around 4:35 a.m. after receiving two reports of a bomb at the school. The first units to arrive spotted a suspicious backpack outside the school near a door.

Police utilized bomb-sniffing dogs and a robot to determine whether the threat was credible. Around 10 a.m. the threat was cleared. By 10:30 a.m. student and teachers were allowed to enter the building.

Toledo, who resides at 5451 Tilalary Court in Burke, was charged with felony threats to bomb and criminal trespass. He was a former student at the school according to multiple reports.