FORT LAUDERDALE, Fla. — The FBI tipster whose call to the agency last month was ignored had warned an employee that she was concerned about Nikolas Cruz “getting into a school and just shooting the place up,” according to a transcript of the call obtained by the South Florida Sun-Sentinel.

The caller, whose name is redacted from the transcript, said she was worried that Cruz was “going to explode.” The woman spoke with an FBI employee for more than 13 minutes Jan. 5, and said she also alerted local authorities.

“I just want someone to know about this so they can look into it,” the woman said. “I just know I have a clear conscience if he takes off and ... just starts shooting places up.”

Cruz, 19, is accused of killing 17 people at Marjory Stoneman Douglas High School in Parkland, Fla., on Feb. 14.

The transcript was first reported Friday by The Wall Street Journal. Congressional staffers were briefed about the call Friday, news outlets reported.

On Feb. 16, the FBI publicly acknowledged that it did not send the tip to the FBI Miami Field Office. Attorney General Jeff Sessions ordered an investigation of how the Department of Justice and FBI handled the matter.

The tipster, whose relationship with Cruz was also redacted, said Cruz bought rifles and ammunition, using money from his dead mother’s bank account, and posted pictures of them on Instagram. Cruz’s mother Lynda died Nov. 1.

“It’s alarming to see these pictures and to know what he’s capable of doing and what could happen,” she said of his Instagram account. He also wrote he wants to “kill people,” she told the FBI.

The tipster said that Cruz had the “mental capacity of a 12 to a 14 year old” and she gave the FBI employee the address for where Cruz was staying, but she said the man he lives with refuses to return her calls.

The woman said she also called police in Parkland with concerns about Cruz and that she “didn’t hear anything.” The Broward Sheriff’s Office, which oversees Parkland, said Thursday that it had received two calls about Cruz. One was in February 2016 and the other in November.

The woman, who called the FBI in January, said she sent a message to Cruz on Instagram, asking him how he was doing.

He responded: “Leave me the f alone.”

shobbs@sun-sentinel.com