Transcript for 15-year-old arrested for allegedly saying he'd shoot up school
And we begin tonight with the disturbing new headline, after El Paso and Dayton, tonight, news of three new threats. Three new arrests. Authorities say these threats of mass shootings in three separate states. Police in Florida hand cupping this 15-year-old boy with his mother by his side. He is accused. These new arrests come on the heels of three other threats. At least a half dozen in the last week. The FBI warning about a rise in domestic terror and possible copycat shooters, and authorities believe this is proof of that. ABC's Victor Oquendo leads us off. Reporter: You're watching police body cam video of a 15-year-old Florida boy, who's face has been blurred, being arrested in front of his mother by two officers for allegedly threatening to shoot up his school. Authorities reading that threat aloud to the teen and his father. I vow to bring my father's m-15 -- He didn't do anything wrong. He's still a little boy and he's not one of the crazy people out there doing stuff. Reporter: Tonight, police releasing the 15-year-old's mug shot, which we've blurred. His comment was reported to the FBI. A written threat is a second-degree felony in Florida. Across the country, police say they've potentially thwarted several mass shooting threats. In Indianapolis, 38-year-old truck driver Thomas Matthew Mcvicker was arrested. Authorities say they stopped him less than a week before he planned on attacking a church in Memphis. In the criminal complaint, police saying Mcvicker said, "I was thinking about shooting a church up, but I'm afraid how it will affect my family in the flesh after I'm gone." And in Seattle, 35-year-old Eric Lin was arrested for allegedly writing on Facebook that he would "Kill all hispanics in Miami and other places." These three arrests make at least six mass shooting threats in the last few days. Including 20-year-old James Reardon from Ohio, who police say threatened to shoot up a jewish community center. And posted this disturbing video on his Instagram. And this dramatic police body cam video. Do you have any weapons we need to know about? Reporter: Capturing the moment Florida officials arrested Tristan Wix in daytona Beach, after he allegedly texted his girlfriend his intenses to shoot as many as he could, writing, "A good 100 kills would be nice." Victor Oquendo with us live tonight. And Victor, authorities on high alert in the wake of these recent mass shootings across the country. And do we know any motives in any of these cases yet? Reporter: Well, David, while we know the FBI warned of potential copycats, no motives have been revealed in any of these six cases. Authorities questioning them all tonight and they continue to urge the public to be on the lookout. David? Victor, thank you.
This transcript has been automatically generated and may not be 100% accurate.