Great. As to your second question of why was he arrested when he was only defending himself, this is a question that many people ask when they are arrested for similar defense of themselves or others. To the police, their only job is to round up anyone they "think" committed a criminal offense and close their file. They then turn the matter over to the state's attorney's office and to the criminal justice system.
To the police, any claim of self-defense is not of their concerns (as unfortunate as that may be and sound, it is the reality of the current state of law enforcement today). Any issues of whether or not someone was defending themselves or others is a matter for the courts to determine, because of the highly fact-intensive nature of self-defense claims.
For one to successfully allege self-defense, they must show that they were placed in a reasonable apprehension of an imminent harm. Factors that go to that determination include: what actions the construction guy undertook, what he said, how close did they get to one another, etc. These facts are, according to police, only for either a judge or a jury to decide. Law enforcement generally just want to close a "case" or file as soon as possible, which is done by an arrest. They want to leave the hard work for judges and juries (i.e., determine if the individual claiming defense is allowed to by law). And, because self-defense is a legal question, an area that law enforcement do not have experience with, they tend to leave those decisions to those who indeed do have experience in the area (judges and attorneys).
So, as unfortunate as it may be, what law enforcement did in this situation is very common across the country. A determination of whether one was lawfully in defense of himself or others are almost always left to the discretion of a judge or jury during the course of a trial.
I hope this has helped. Please let me know if you have any follow up questions based on what I have provided or need clarification on any point. I would be happy to discuss further.
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