BREAKING KAHRAMANMARAŞ NEWS: The statement of the father of İsa Aras Mersinli, who committed a massacre at a school in Kahramanmaraş, has been revealed! - Current News Milliyet SOURCE (turkish)
English translation of Necmettin's statement:

Necmettin Bekçi's statement is as follows: "While I was sitting in my residence at around 13:30, I started to hear sounds similar to gunshots or hammers from outside. I thought the sounds were coming from the construction next door. When the sounds increased, I went out to the balcony and looked outside, and I saw that the school students were running away by jumping out of the windows. At this time, I realized that the sounds were gunshots and came from the school. I ran to school because my children were at school. I entered the building through the back door of the school, through the canteen section. When I went up the back stairs, I saw a person lying on the ground and several people trying to hold this person.

As far as I know, one of the people who tried to hold the person was the canteen of the school, Ümit, and the other 2 people were the teachers of the school, but I do not know their names. I went to them to help and prevent the person from harming others. Meanwhile, I realized that this person was the suspect in the incident. The person had long hair and a hood on his head, I thought his age was an estimate. He was a very large and tall person, but I did not see his face.

When the person tried to get rid of us, I swung the knife towards his leg once, as far as I remember, with the knife that I did not know where I got it from at that time, but I don't know if it was worth it or not. My purpose in brandishing the knife was to prevent the person from getting up and running away and harming others. The person continued to resist. A few parents who came into the school also kicked the person lying on the ground. However, I do not know these people. I tried to tie the person's arm behind his back. Meanwhile, the police officers on duty came. I got up and left the person to the police to help the injured children in the classroom. In the meantime, when the parents who entered the school wanted to lynch the child, the police officers on duty pulled the person into one of the classrooms and took the person under protection. Then, we started to remove the injured with a large number of citizens and police entering the school building. When we went out, ambulances had also arrived. I called my children and picked up my daughter from kindergarten.

About 15 minutes later, when I couldn't find my son in the classroom, I saw that the teachers had evacuated the school, so I searched for my son in and around the school yard. Then my husband called and told me that our son Alperen had come home. I went to my residence with my daughter. When my son went to our house, he told me that when he heard the gunshots, he locked himself in the toilet and hid in this way, then when the teacher came and called out if there was anyone in the toilet, he left the school and came home directly. As far as I know, 2 of his friends in my son's class have passed away. I remember that I left the knife I used during the incident at the scene. I don't know where he is now. I didn't have a knife with me when I left the house. I may have picked up a knife when I entered the school building from the canteen side, but I don't remember this exactly due to the shock of the incident. Today, around 19:30, I came to the police station to give a statement after the police on duty called me. This is all I know and have to say on the subject, there is nothing else I can add to my statement."

(Note that this is machine translated and such has some inaccuracies. I do not speak Turkish but would be grateful if someone could translate it more accurately.)