At least 14 people, including three teachers, two caretakers and the hostel manager, have been detained for questioning.
Six-year-old Sare Betul Genc was not meant to be at the girls dormitory which caught fire on Tuesday evening in the Aladag neighbourhood of Turkey's Adana city.
Her father, who is the building manager, left her at the hostel to be looked after for a few hours while he was busy elsewhere.
By 7:30 pm, the hostel — for girls attending middle school around Adana — was on fire. By 10:30 pm one tutor and 11 children had died in the blaze, including Sara.
At least 14 people, including three teachers and two caretakers, were detained on Wednesday as part of the investigation into the incident. Sare's father was also among the detained suspects.
The hostel is run by the Aladag Association to Assist Students of School-going Age and the rest of the detained suspects are affiliated with this body. Three prosecutors have been assigned to the inquiry opened up by the state.
Turkey's Deputy Prime Minister Veysi Kaynak said that according to the initial investigation, the fire was caused by an electrical fault. He also denied reports that the building's emergency exit was inaccessible.
There were 34 people inside the dormitory when the fire erupted on Tuesday evening. Some of the 22 survivors managed to escape the blaze by running to the second floor of the building from where rescue teams were able to evacuate them.
A few others jumped from windows to save their lives.
Two of Ahmet Yetim's daughters were at the dormitory at the time of the blaze. Sumeyye, a seventh grade student, was burnt to death. Fadime, a fifth grader, survived.
"We ran to the second floor, and the firefighters used their ladder to reach us and help us down. My sister was on the third floor," said Fadime. "We were really afraid."
Yetim wept as he spoke to TRT World about his family's desire to educate Sumeyye and Fadime despite the prohibitive distance from their village to the girls' school.
Many of the affected families live two to three hours away from their children's schools and opted to house them in the hostel instead.
Neslihan Aydogdu, another student, also shared her experience of the horrors of Tuesday night. "When we saw the fire, we immediately ran up to the second floor," she said.
"We broke the windows when the fire fighters came and they pulled us out using ladders."