The teenager who killed 8 children and a school guard in a shooting spree in a school in central Belgrade earlier this week, was not under the influence of psychoactive substances when he committed the crime.

The lawyer of the boy’s family told Serbian local media that the teenager had been tested for substance use at the Military Medical Academy in Belgrade, and his results came out negative.

She also said that the teenager had been interviewed by a team of doctors at the Child and Adolescent Neurology and Psychiatry Clinic in Belgrade. The boy is to undergo further examinations in the coming days.

Six children and a teacher were wounded during the attack. Two of the wounded children are reportedly in critical condition.