Newly released documents have revealed more disturbing details about the mind of Nikolas Cruz, the man suspected of fatally shooting 14 students and three staff members at Marjory Stoneman Douglas High School.

On Monday, Florida authorities released a 217-page interrogation transcript in which the 19-year-old confessed to carrying out the massacre. Cruz, who was arrested shortly after he opened fire, reportedly told investigators there was a “demon" voice inside of his head that instructed him to “burn, kill, destroy.”

“I hear demons [...] a voice, demon voice,” he said, according to the partial transcript obtained by CBS Miami. “The voice is, is in me [...] To me, it's me and then my bad side [...] It's a voice. The voice is in here and then it's me, it's just regular me, just trying to be a good person.”

Cruz claimed the “voice” directed him to purchase an AR-15 and that a he initially planned to go to a public park and kill people prior to the Parkland shooting. He also said he attempted to kill himself multiple times before the massacre.

“Personally, I think you're using the demon as an excuse,” Det. John Curcio of the Broward County Sheriff's Office told Cruz, according to the transcript. “You could have stopped the demon any time you want. You didn't want to stop the demon.”

“No, that’s not true,” Cruz replied.

“You didn’t. You could have,” Curcio said. “[…] Now you’re just acting like that that because—”

“No. No. No. No. No. No. No. No,” Cruz said.

“OK. Well, relax,” Curcio told him. “You’re just acting like that because I’m making sense.”

“[…] I don’t like the demon,” Cruz responded.

“That’s if the demon even exists.” Curcio said.

“Can I get an attorney or something?” Cruz asked.

Following the interrogation, Cruz was booked on 17 counts of murder and 17 counts of attempted murder.