Are plain clothes police officers allowed to use force to make an arrest?

Question

Disclaimer: I'm not related to this case in any way shape or form, I'm just a citizen trying to look at this without bias.

Recently there was an issue in Massachusettes where a group of skaters were asked to leave the premises, a police officer confiscated a board from one of the skaters, but the skaters said they were leaving, they just wanted the board back.

Obviously, the skaters are in the wrong for skating on public/city property (and grabbing the board from the officer), but I don't think a trespassing charge like that should outweigh possible misconduct of a group of officers.

During the disagreement, another skater went to rip the board out of the officers hand and run off, at which point a non-uniformed cop stepped in and tackled the skater. While going down, the officer and skater exchanged blows, when asked by the court, the skater said he wouldn't have punched him had he known it was a cop. So instead of getting an assault/battery charge, he now is trying to be pressed with assault/battery of a police officer (albeit, non-uniformed, non-identifiable).

However the new has been putting a focus on the use of force in the case. Considering, while the first tackle was going down, another individual was seen in the video cussing out the officers and walking away. At which point, you hear an officer yell grab him and the skater runs off, to get tackled by another officer.

My main question here is, how can a non-uniformed/non-identified cop try to stick an assault/battery of an officer charge on someone, if the only people at the scene who know he is an officer, are the other officers.

I used to skate, but am trying to look at this unbiased, as I've seen plenty of citizens try to step in and be vigilantes, so the thought that the one skater believed he was being tackled by a random bystander doesn't seem super far-fetched.

Attached is the news article of the incident, which includes a break-down video of the altercation.

Answer 1

Police officers are authorized to use force regardless of what they are wearing, to effect an arrest. One issue will be whether the defendants should know that they were under arrest, but there is no requirement to utter particular phrases when dealing with a combative lawbreaker. There will be an internal investigation at some level to determine whether the officers violated any department policy, and no doubt the video and testimony of those in the are would be relevant. There probably is some policy to the effect that you have to distinguish yourself from a street vigilante (you have to state your authority), though I can't find any specific online publicly-available department rules. There is no law that requires an officer to say that he is one, or to show his badge, before starting an arrest.