RAMONA, Calif. -- Deputies were stationed at Ramona High School Monday to allay concerns about the arrest of a student who allegedly threatened to cause "significant destruction" at the campus, a sheriff's official reported.

Korey Robert Flad, a 19-year-old senior, was taken into custody at his home shortly after midnight Sunday, Lt. Duncan Fraser said.

Authorities got word Friday that a student at the Hanson Lane secondary school had made comments about doing violence there, the lieutenant said.

"The initial information was that on a future date the student, acting alone, intended to cause significant destruction to the school," Fraser said, but declined to provide specifics about the purported threats.

On Saturday, deputies, working with Ramona High School Assistant Principal Dave Lohman, identified Flad as the suspected perpetrator and discovered the identities of possible witnesses to his alleged menacing statements.

"The criminal investigation is ongoing, but initial information obtained by investigators has confirmed that Flad acted alone and (that) his threats were verbal in nature," Fraser said. "The investigation has also revealed that Flad's threats were not against specific persons."

Flad, a Ramona resident, was booked into Vista Jail on suspicion of making criminal threats, threatening a school and threatening to use a weapon of mass destruction.

School Principal Tony Newman used a telephonic-message system Sunday to inform students' parents about the arrest and to assure them that their sons and daughters would be safe in attending class Monday.

Deputies were stationed at the campus Monday morning to allay families' concerns and to answer any questions about security at the school, Fraser said.