Nikolas Cruz was reported to the FBI last year after boasting of plans to be 'a professional school shooter': report
Police arresting a suspect at Marjory Stoneman Douglas High School after an active shooting. Image via Twitter.

Nikolas Cruz, the 19-year-old man suspected of carrying out a massacre at a high school in Florida on Wednesday, was apparently on the FBI's radar last year after he posted a comment on YouTube about wanting to be a "professional school shooter."

BuzzFeed reports that 36-year-old YouTube user Ben Bennight alerted the FBI about a comment left on one of his videos by a man who identified himself as Nikolas Cruz.

"I'm going to be a professional school shooter," Cruz wrote.

Bennight said the FBI responded to him immediately, but he said they didn't have any followups after their initial meeting in September.

"They came to my office the next morning and asked me if I knew anything about the person," Bennight said to BuzzFeed. "I didn't. They took a copy of the screenshot and that was the last I heard from them."

Bennight said he did hear from the FBI on Wednesday after Cruz allegedly killed 17 students at the Marjory Stoneman Douglas High School in Parkland, Florida.

"I think we spoke with you in the past about a complaint that you made about someone making a comment on your YouTube channel," an FBI agent said in a voicemail left in Bennight's inbox. "I just wanted to follow up with you on that and ask you a question with something that's come up, if you wouldn't mind giving me a ring."

President Donald Trump on Thursday encouraged people to report others who exhibit "erratic behavior" to authorities at all times. Based on BuzzFeed's report, it appears that that happened in this case, although it did not prevent a massacre.