UPDATE: Pittsburgh police have issued a statement on the protest and their investigation, which also involves the FBI and the U.S. attorney in Pittsburgh. Click here to read the full statement.PREVIOUS STORY: Pittsburgh police are investigating after two viral videos showed protesters clashing with the public at a downtown protest Saturday.One video shows a demonstrator nudge a man, who is carrying a bike, in the head. The man turns around and slaps the megaphone. The man is then slapped in the back of the head.The second video shows demonstrators yelling at patrons of a restaurant, calling them an embarrassment among other things. Some customers grabbed their belongings and walked away.A couple who stayed at their table were approached by demonstrators, one of whom grabs their beer and drinks it. Another demonstrator grabbed a glass and threw it down.Activist Lorenzo Rulli spoke out on Monday and said the videos don't show everything that happened."There was an agitator in the crowd who was being aggressive and physical with peaceful protesters," he said. "We do what we do to keep us safe in any capacity when the police do not engage when it is their time. It's your time to engage when someone is throwing blows at peaceful protesters."Rulli said the biker in the video drove through the crowd and engaged violently with protesters."The biker drove through the protest and instead of taking heed to the fact that there was an issue with the noise amongst his group, he actually got off of his bike and engaged violently. He put his hand on someone's breast," he said. "So when we got to the point when he was being engaged, I no longer even cared because I saw him put his hands on someone's breast. My job now is to engage the people who are watching and educate them on what's happening, and that's what we began to do."The second video shows a confrontation outside of a restaurant."People eating at the restaurant, sat there, some of them cheered us on because they saw what happened in its entirety," he said. "Some of them asked what was going on. Some of them made really negative statements so I stopped and I addressed that statement and I also addressed a woman who wanted to hear what was going on. To hear why we had to march right through there. Why we were talking to them. A lot of people are saying we're targeting the businesses, but that's not the case. We eat at these restaurants. We know most of these owners downtown. They invite us into their spaces. They bring water out for us when we march. We sat there and watched the employees cheer us on because it was not an attack on the restaurant."People were starting to get aggressive towards us because they didn't see what happened. But the other people actually didn't care. They got up out of their seats and moved to the side so that we could address the people who actually were making remarks," he said. "Like, 'oh we're an embarrassment and we're disgusting.' But we can't be the embarrassment and disgusting people when we're peacefully saying stop killing our brothers and sisters and someone can come in and throw blows."The Saturday protest carried into the evening when demonstrators marched to Mayor Bill Peduto's home.Pittsburgh's Action News 4 reporter Katelyn Sykes has reached out to the woman who shared the videos to Facebook for more information. She is still waiting for a reply.Officials said there were no arrests during Saturday's protest."We were having a conversation and we were loud, because when we whisper no one is listening," said Rulli. "We're not targeting anyone. We are marching and being targeted as the police watch."Early Sunday morning, Peduto tweeted, "Tonight at my home - private property. The 1st Amendment doesn't protect you to close down streets, without a permit. Yes, we have granted extra rights to assure free speech. But, continual denial of law, will end up in arrests. Actions have consequences""We abide by the laws in our marches," said Rulli. "We don't have to have a permit to protest. We don't have to have a permit to be black and he shouldn't put one Black activist at the forefront of a whole movement in his city and say go for this person. That's dangerous and it's unbecoming of a mayor."A spokesperson for the mayor's office said they had no additional comment on Monday."I want people to know that we don't bully people because it doesn't get us far," said Rulli. "We were engaging people who did not support and who were considering support. We talk to people just as much as we yell. But if you hear my voice don't consider it aggressive. Consider me loud, black and proud."On Tuesday morning, President Donald Trump tweeted about the incident.