Update: Yonata Getachew was sentenced to probation before judgment, which he has completed, his attorney tells News4. For updated coverage of this case, click here.
Anthony Torrence, 17, and 18-year-old Yonata Getachew are charged as adults with conspiracy to commit first-degree murder, three counts of arson, and conspiracy to manufacture or possess a destructive device.
Authorities discovered their plot Tuesday. There's no evidence they planned to execute the attack Tuesday, police said.
"They'd been planning over the past four weeks to assault a school counselor and the school's principal with explosive devices and set fire to the school building using explosive material to cause extensive damage and serious injuries to others," Police Chief J. Thomas Manger said.
Principal Michael Durso called it a sobering discovery.
The teens also face reckless endangerment charges.
"That stems from a plan involving setting fires, trying to break open a gas pipe and using that to create an explosion or fuel a fire, which could have harmed students in the school," Manger said.
The investigation began with a report of an attempted arson in the ROTC hallway and a boys locker room, detectives said. School security stopped two students apparently leaving the school.
One of the suspects confessed to the police officer assigned to the school, sources said.
Searches of the suspects' homes discovered chemicals used in making chemical reaction bombs, flammable liquids, a carbon dioxide cartridge, nails, balloons, homemade wicks, fireworks, and notes and plans about preparations and the physical design of the school, according to police.
According to court documents, the teens planned to attack a school counselor with a bag of rocks and nails because one of them hated her and bomb the principal because of the way he backed the counselor up.
Durso sent a letter to parents about the arrests.
"We learned yesterday that plans were being made that could have resulted in damage to the building, as well as potential harm to students and staff," Durso wrote.
Arson investigators suspect the teens in at least one fire at the school, a source told the Washington Post.
Getachew's friends and relatives said such behavior is out of character for him.