Transcript for Inside the ‘Boogaloos’: Extremist movement makes its presence known at demonstrations
Reporter: Those aloha shirts, they're not for a luau. Igloo, masks and packing heat. The leader of this group goes by the name "Shifty." It's not his real name but a nickname he gave himself, but he is a self-proclaimed boogaloo boy. He is meeting with about a dozen others to adend this black lives matter March. Serving as an armed protection to keep protesters safe from violence by the police. His group is armed and ready with assault rifles. And in this minds they say they're guarding against what they describe as government intrusion. Boogaloos don't often speak to the media, but he agreed to an interview with me via speakerphone just before the protest. What's with the hawaiian shirts? We needed something to identify ourselves with. Reporter: I know you're not trying to seem menacing, but an a.r.-style rifle is menacing. Everybody who does such in my group is trained and efficient with their weapons. Reporter: But shifty and his fellow boogaloos are not part of black lives matter. They're part of a different and much more secretive group. They're pro-freedom but civil war two, electric boogaloo. Did is referencing an old movie from 1984. Reporter: You might ask what is involved in teens in break dancing duels have anything to do with armed men, hawaiian shirts and call for civil war? Not much, actually. First reference to the boogaloo future civil war started in the recesses of the internet a few years back and crossed over into more mainstream social media platforms and caught steam. Reporter: The word is a throw-back to afro-latino dance. This group is deadly serious. They are an extremist group. Their rhetoric, their pedigree and everything is based on violence against peace officers and others that they disagree with. In general, there are two broad camps of the boogaloo. On the one hand, you have white supremacists who view this through a racial lens and the more popular anti-government extremist version. Reporter: Some members have been accused of using the protests to act on boogaloos' violent promise of inciting discord. Several have been charged with crimes. In Las Vegas, federal authorities say three alleged members were found possessing molotov cocktails, they were arrested and charged with federal and state crimes, including a conspiracy to commit acts of terrorism. All three men have pled not guilty. And in Oakland, authorities say air force sergeant Steven cario who had posted about the movement online and Robert justice Jr. Drove this white van to the federal courthouse there and shot and killed federal officer, Patrick Underwood. They came to Oakland to kill Reporter: A week later, a witness spotted that van 70 miles away near Santa Cruz, California. The witness observed ammunition, firearms and bomb-make being equipment in the van. Reporter: The van was followed back to cario's home where they say he ambushed officers, fired on them and threw explosives. Another officer, Damon gut S Wyler was killed. Somebody please come help! Reporter: Finally, a good samaritan tackles him and police find what they say was a ghost gun, a homemade a.r.-style rifle he'd allegedly used. And as he was led away, cario yells. . Reporter: Authorities say cario scrawled in blood on one of the vehicles he stole, and in the van, a bullet-proof vest tying him to the movement. He has been indicted and faces charges of murder and attempted murder, both have pled not guilty. He was a lone wolf. We do not condone violence or his actions. They were disgusting. He was not doing that in the defense of anybody's individual liberty. Reporter: Do you think it's a problem for the boogaloo that people identify them with Steven's alleged attack on police? Yes, it has been harmful to some things with us, yes. Reporter: You've turned people away who have been advocating violence. Absolutely. Reporter: But these boogaloos claim they are non-violent and have become a self-involved fixture in protests across the country, never formally invited but making their presence known. One of the methods of recruit something joining these protests and putting on a positive face that they are joining the people. Reporter: This is another member who wants to be called "Trashman". He works construction during the day and runs a group on Facebook. I first became involved or aware of it through social media, through Facebook. Reporter: Trashman isn't carrying a gun because he says he's a non-violent boogaloo. What brought me to this ideology was the inclusion of others. It's not relegated to a certain class of people or color of people or religion. Reporter: Sounds pretty middle of the road, but despite their claims of non-violence, homeland security and the department of justice have labeled them as a violent extremist group. The biggest misconception of the boogaloo movement is that we're racist terrorists or extremists of any kind. Reporter: Facebook and discord recently categorized them as extremists. In July we shut down on Facebook. My personal profile as well as from what I understand hundreds as well as thousands of others were permanently deactivated on Facebook. It was a smack in the face for sure. All they did was fracture us into a thousand more harder-to-find pieces. It didn't slow us down one bit. Reporter: Even with the burgeoning attention, they remain very cloak and dagger, but shifty feels they need to capitalize on the wave of unrest sweeping the country. Why is it important for you to do this interview, shifty? Too many times we do not get a sit-down and a relaxed environment to really express our views and really get the word out for what we're standing for in face and let people know this isn't just an internet meme or a bunch of guys sitting in their mothers' basements taken on key borsd. This is a real thing. Reporter: They stand at the ready. The reality of the ethos is always present. How far are you willing to go, even at a protest, the blm protest? There's always the phrase live to fight another day, but everybody in our group is prepared to give the ultimate sacrifice in defense of liberty. Our only recourse at this point is to be louder than everybody else, where we need to make our voices very clear and very loud to both unify us and distance ourselves from those that would cause harm to people or present us in a bad light. I think their ideology and everything tells you exactly what they're here for. Are they here to stay? I, I think time is going to tell. These groups don't go away. They may morph, change their name, change their style, change their membership. But the ideologies usually don't change. Reporter: For "Nightline," I'm Matt Gutman in Los Angeles.
This transcript has been automatically generated and may not be 100% accurate.