What started off as a casual morning event full of free swag, complimentary Dunkin’ cups of coffee and potted plants quickly turned into a violent altercation during Mayor Michelle Wu’s “coffee hour” in Ronan Park on Wednesday.

One man was arrested at the scene in an altercation with police officers yards from the mayor.

Police told the Reporter that Shawn Nelson, 43, of Dorchester, was arrested at the event for resisting arrest, disturbing the peace, and violating the city ordinance by using a bullhorn. Police said the use of a bullhorn was in violation of the permit for the event.

The coffee hour, traditionally one of the tamest events on the Boston mayoral calendar, started without a hitch, with residents and the elderly getting fruit cups, collecting potted plants given away for free, and grabbing a cup of coffee from Dunkin’ Donuts while meeting their elected officials and city department employees.

About 20 minutes into the event, protesters who have spent months harassing the mayor over COVID-19 policies, began using bullhorns and began yelling slogans, mostly vulgarities, aimed at Mayor Wu.

Boston police officers began to try to separate the protesters in the lower park from the scene of the event, which was based at the overlook point of Ronan Park.

Boston Police said they first encountered the protesters at about 9 a.m. prior to the event and recognized them from previous protests. Police told the group that bullhorns would not be allowed at the Coffee Hour due to the permit pulled by the Parks Department – which only allowed a DJ for the event and an amplified microphone for speaking at the event. Police said they would confiscate any bullhorns that they found being used.

Nelson disagreed with them and said police would not take his bullhorn and would not touch him at the event.

When Mayor Wu arrived at the lower side of the park around 9:30 a.m., Nelson began to yell into the bullhorn nearby. As a crowd of residents, children and the elderly began to gather by Wu, Nelson suddenly began to scream and flail his arms and kick his feet.

Police surrounded him and tried to subdue him, and he turned and began running in Wu’s direction, with several officers hanging from him. More officers jumped in and brought him to the ground as other protesters surrounded the scene.

Police said Nelson got agitated when police confiscated his bullhorn, as they told him they would do, as well as a sharp disagreement he had with a member of the public in the crowd. When police seized the bullhorn, he grabbed on to the handle and tried to pull it away. As police removed it, he held on and moved quickly in the direction of the mayor in an attempt to re-gain control. It was during that struggle that police had to take him to the ground and subdue him.

Two officers sustained minor injuries in the melee.

After Nelson was handcuffed, he refused to walk to the police vehicle. Boston Police said they had to carry him to the vehicle and place him inside.

Following his arrest, the COVID-19 protesters continued to attempt to disrupt the coffee hour as Mayor Wu and Councillors Brian Worrell and Frank Baker sought to address the crowd. A group of the protesters was seen shouting at a young boy and his mother who tried to take a picture with the mayor, and also yelling at a local priest.

The coffee hour is part of a series of events in the park every summer, and this was one of the last ones to take place. The same protesters disrupted a coffee hour at Garvey Park last month, but not to the extent of the event at Ronan Park, observers told the Reporter.

“Our Neighborhood Coffee Hours are an opportunity to speak directly with residents in our communities and address constituent concerns right away with city staff from many departments present in our parks," Wu said in a statement to the Reporter. "I’m grateful to the Boston Police Department for their quick actions this morning to ensure our residents could safely enjoy today’s coffee hour at Ronan Park.”

This post was updated with Mayor Wu's statement.