"According to the investigation, Ilnaz Galyaviev did not have a psychiatric or drug abuse record. However, we have learned that he requested medical assistance for strong headaches multiple times. Back last year, after visiting a medical facility he was diagnosed with a brain disease. His relatives were noticing his aggressive and irascible behavior at the beginning of this year," Petrenko said on Wednesday.
The official added that the young man's condition prevents him from being investigated.
"His current condition is marked by erratic behavior, which prevents investigators from working with him at the moment," Petrenko stated.
The 19-year-old man, who was officially registered as a gun owner, was detained on suspicion of opening fire inside the school in the main city of Russia's Republic of Tatarstan on Tuesday. According to Tatarstan's authorities, seven children and two female teachers were killed and 23 more people were injured in the tragic incident.