Authorities near Cleveland have arrested the man they say e-mailed the boy about conducting the attack on two schools.
Lakewood Police Chief Tim Malley says 33-year-old Lee Billi was charged Thursday with conspiracy to commit murder. The 16-year-old boy appeared in an Indiana courtroom Friday morning in the case.
Malley says he doesn't know how far along the two were in their alleged plans.
Authorities say the two exchanged e-mails Sunday in which they discussed mass murders at the same time at the teen's school near South Bend and at another location. A computer was removed from Billi's home in Lakewood in a search Thursday. The pair also wrote about researching how to obtain weapons and make explosive devices. The teenager, a freshman, asked Billi to help him obtain a TEC-DC9 9mm pistol, stating it would be "awesome" if he could use the same weapon used in the Columbine shootings, St. Joseph County, Indiana Prosecutor Michael Dvorak said.
Billi is being held in jail and is expected to be arraigned by Saturday.
Authorities detained the teen Tuesday on an initial charge of intimidation, Dvorak said Thursday. His office was preparing charges of conspiracy to commit murder after authorities found more than 100 knives at his home, Dvorak said.
Authorities also found several illegal snakes at his home in Mishawaka, about 10 miles east of South Bend, Dvorak said. The boy was being held Thursday at a juvenile detention center.
A school officer investigating an unrelated threat at Penn High School discovered Internet postings in which the teen discussed his support for the Columbine shooters, Dvorak said, a reference to the 1999 massacre at a suburban Denver high school in which two students killed 12 classmates and a teacher before committing suicide.
School officials questioned the teen about his postings and learned he had exchanged e-mails Sunday with an unidentified person in which they discussed conducting "Columbine-like mass murders" at the same time on Sept. 11 at Penn and another location, Dvorak said.
Teresa Carroll, spokeswoman for the Penn-Harris-Madison School Corp., said the other location was in Ohio.
Police searched the student's locker, backpack, home and laptop computer and found notebooks in which he wrote about killing a large number of people. They found he had searched the Internet on Monday for how to make propane tank bombs and for a reference guide on how to make explosives and other dangerous devices, Dvorak said. The teen also searched for 9mm guns, he said.
A juvenile court hearing was scheduled for Friday to determine whether the teenager should remain in custody.
Meanwhile, prosecutors in Columbia, S.C., sought a mental evaluation for an 18-year-old accused of planning to bomb his high school.
Ryan Schallenberger should be examined to determine whether he understands the case against him or can help with his defense, federal prosecutors wrote in a motion filed in federal court.
The teenager is in the Chesterfield County jail. He was arrested April 19 and faces several state and federal charges, including attempting to use a weapon of mass destruction. That charge carries a possible life sentence if he is convicted.
Authorities have said Schallenberger's parents called police because he had ordered ammonium nitrate, which was used in the deadly Oklahoma City bombing in 1995.
Michael Meetze, Schallenberger's public defender, declined to comment Thursday.