Suspect arrested after allegedly posting video showing rehearsal for mass shooting

Authorities arrest man in San Diego over fears of another mass shooting plot.
2:23 | 12/08/19

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Transcript for Suspect arrested after allegedly posting video showing rehearsal for mass shooting
We do start with chilling images sparking fears of another planned mass shooting. Authorities arresting a man in San Diego they suspect may have been rehearsing a deadly plot and Marci Gonzalez joins us from our Los Angeles bureau with more on that story. Marci, good morning to you. Reporter: Whit, good morning. It is unserving to watch. It is unserving to watch. The man wearing what appears to be a body camera and enacts a violent takedown of people walking below his hotel room. Someone who claims to know him spotted the videos on YouTube and alerted the FBI. This morning, the suspect police say posted videos of himself carrying out what they call a rehearsal of a terrorist mass shootings in downtown San Diego under arrest. According to court documents, the chilling images show a man inside a room at the Sophia hotel repeatedly aiming and pretending to shoot people. The man identified by investigators as 30-year-old Steve homoki is seen changing out magazines and guns showing at least two assault-style rifles and ammunition scattered on the floor. It sounds like Stephen paddock in Las Vegas a couple of years ago. And so that's why it's so alarming. When people see this, they think are we going to have to relive Las Vegas? Is this guy actually -- is this a dry run for him? Reporter: The videos were posted in September. But according to the search warrant, the FBI didn't learn about them until more than two months later from an anonymous tip. The tipster said the suspect had gone off the deep end reporting fears that he's planning something and concerns if confronted while at home, he will open fire on federal agents or police. Authorities arresting homoki at his home without incident on charges including possession of an assault weapon and high capacity magazine. Investigators saying the fast response neutralized a very real threat praising the investigation as truly extraordinary. You take every tip seriously because you just don't know if it's going to be a real shooter or not, and unless you check it out, you're not going to know. Reporter: Police say they learned homoki had 14 registered guns, at least one of which they believe may have been illegally modified. He is now being held on $20,000 bail and is expected to be arraigned tomorrow. Dan. Marci, thank you. As you said, those images are horrifying. We appreciate, it though.

This transcript has been automatically generated and may not be 100% accurate.

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