CCTV footage appeared to show the suspect walking through empty streets checking a shotgun, which is clearly visible. He is casually dressed and appears unhurried.
Later footage showed the apparent suspect, who is reportedly a student at the school, running from the scene with the weapon still in hand.
The motive behind the attack was not immediately clear.
According to Turkish law, the teenager is required to appear before a court before being officially arrested.
In a statement, Turkey’s education ministry said the incident had “deeply saddened our nation, and our educational community in particular”.
It said that three national investigators from the ministry had been sent to Manisa.
Two deadly school shootings in April caused outrage in Turkey and led to new security measures for the 2026-2027 academic year, including tighter gun controls.
Before then, the country did not have a history of school shootings.
In an attack in Kahramanmaras, a 14-year-old killed nine students aged 10 and 11, and one teacher. The gunman died at the scene.
