He was a naturalized citizen. He was legally afforded all the rights you have except he can’t run for president.
That didn't stop Obama, did it?
One of the brothers is/was a green card holder. I was going to ask why he could buy/possess a gun, but apparently green card holders can buy a gun by federal law, at least. I did not know that.
Anyhow, I am still curious as to what guns they had if they were legally purchased/possessed in Massachusetts.