Someone close to alleged Florida school shooter Nikolas Cruz warned the FBI in January that she was concerned Cruz would commit a mass shooting, according to a transcript of her call with the FBI.

The Wall Street Journal released a transcript and CBS News released audio Friday of the January 5 FBI call, which shows a detailed record of the woman’s efforts to warn authorities about Cruz’s violent tendencies and his history of trouble.

“You know, it’s just so much,” she said on the call. “I know he’s—he’s going to explode.”

The anonymous tipster said she placed the call because she wanted a “clear conscience if he takes off and, and just starts shooting places up.”

The FBI acknowledged last week that they received the call, but this is the first time the explosive allegations within the call were made public.

The caller said Cruz had the mental capacity of a 12- or 14-year-old because she said she found some of his Instagram posts that said he wanted to kill himself.

“Something is gonna happen,” she said. “Because he’s, he doesn’t have the mental capacity. He can’t, he’s so outraged if someone talks to him about certain things.”

The caller went into detail about Cruz’s disturbing behavior, such as cutting up frogs and birds on his mother’s kitchen table.

“He brought the bird into the house,” she recounted. “He threw it on his mother’s kitchen counter and he started cutting it up. He has all kinds of hunting knives. I don’t know what knife he used, though. And he started cutting the bird up, and his mother … said, ‘What’re you doing?’ And he says, ‘I want to see what’s inside.’”

“That to me would be a red flag,” she added.

She also gave the FBI the usernames of Cruz’s social media accounts, urging the agency to examine them.

“It’s alarming to see these pictures and to know what he’s capable of doing and what could happen,” the caller said. “He’s [been] thrown out of all these schools because he would pick up a chair and just throw it at somebody, a teacher or a student, because he didn’t like the way they were talking to him.”

The FBI had been warned about Nikolas Cruz since September, when YouTube user Ben Bennight emailed the FBI tip line to report a comment from Cruz that said, “I’m going to be a professional school shooter.” Although agents followed up with Bennight, they never acted on the tip.