A former friend and classmate of Nikolas Cruz, 19, who is accused of shooting and killing 17 people at a Florida high school last week, says she reported him to school officials on more than one occasion because of disturbing behavior, according to ABC News.

Ariana Lopez spoke with ABC’s Good Morning America on Tuesday and detailed the dangerous behavior shown by Cruz.

“He posted pictures of 15 or more firearms just on his bed,” Lopez said. “He talked about killing our parents, our friends, boyfriends and girlfriends.”

Cruz is suspected of using a semiautomatic weapon in the killings.

Cruz reportedly opened up to Lopez and spoke about his family, including his mother, who died from the flu in November. 

ABC News reported that Lopez told school officials about Cruz’s behavior “multiple” times between 2016 and 2017.

Lopez, who hid in a closet during the massacre, says she was not surprised that Cruz was suspected in the attack.

“I knew it; we all did,” Lopez said. “He was the only person that we can think of that would do something like this because it was obvious that he had the power to do this.”