Russian authorities have charged two teenage boys with attempted murder after what officials now say was a pre-planned attack that injured at least 12 people at a school in the city of Perm earlier in the week.
The Investigative Committee said in a statement that the boys -- one of them a 10th grader at School No. 127 and the other a former student there -- will be jailed upon their release from the hospital.
They are charged with multiple accounts of attempted murder, and of plotting the attack in advance.
Initial reports about the January 15 incident suggested it was an attack by intruders, but Russian authorities described it as a knife fight between two boys and said several pupils and a teacher were injured while trying to break it up.
The new statement said investigators believe the boys entered the building armed with knives, went to a room where an elementary school class was being held, and "deliberately" inflicted knife wounds on a female teacher and nine pupils.
It said the boys also stabbed each other and were hospitalized after the attack.
The Investigative Committee also said it was "evaluating the actions or inaction" of school employees, parents, and those responsible for security at the school, suggesting it was seeking to determine whether anyone else was culpable.