WRENTHAM - Charges have been dropped against a 16-year-old King Philip Regional High School student who was arrested last week for allegedly making threats to shoot other students.

The Norfolk County District Attorney's Office Monday had Juvenile Court in Dedham dismiss the charges of conspiracy to commit murder and threatening to commit a crime, police Detective Sgt. William McGrath said.

The alleged threats were not specific, McGrath said, and a "followup investigation revealed that as to the conspiracy element he was charged with, any conspiracy element requires two or more people. And in this case, the co-suspect was not a viable suspect."

That co-suspect was a 16-year-old student who attends a private Walpole school and told officials at his school about the alleged threat. Those school officials contacted Walpole police, who called Wrentham police.

"There is another investigation involving the same 16-year-old juvenile," McGrath confirmed of the KP student. "Until such time as charges are filed, I can't talk about it." The student was arrested last Wednesday and placed in the custody of the state Department of Youth and Services in New Bedford and held overnight.

He was arraigned Thursday in juvenile court and held on $10,000 bail.

The youth was released after his parents posted bail, according to his attorney, Joseph Cataldo of Franklin.

Police also searched the youth's Wrentham home but found nothing of significance, McGrath said.

King Philip parents and students were notified of the situation by ConnectEd, the school system's new mass phone calling system. A letter was also sent home with students Thursday.

School committee Chairwoman Clare Sullivan said Monday night she couldn't comment on the matter.