Lyela Sayarath, an 11th-grader at Apalachee High School, told CNN that she was sitting next to suspected gunman Colt Gray, 14, shortly before Wednesday’s massacre.

The 16-year-old student said Gray left the classroom at the start of Algebra I class that morning.

Sayarath said the suspected mass murderer knocked to be let back in because the door automatically locked behind him.

A girl tried to open the door for him, but quickly jumped back after probably seeing that Gray was armed.

“I guess he realized we weren’t going to let him in,” Lyela told CNN. “And I guess the door to the classroom next door was open, so I think he just started shooting in the classroom.”

The junior said students in her algebra class hid behind their desks when they heard gunshots. It was a harrowing experience, she said, as they heard “one gunshot after another.”

“When we heard it, most people just dropped to the ground and crawled around in one area as if they were stacked on top of each other,” she said.