On I-751, it says that if I have ever been arrested or detained I need to submit a statement that no charges were filed.
Last year, I was taken to hospital by police after an argument (I had been recently diagnosed with bipolar, it was argued that I was unstable, was found to be stable by all staff at the hospital and left after a few hours); I was never even specifically told I was detained (and police left as soon as I was in the ER area), although I imagine they would have stopped me had I tried to walk away.
Does this count as detained? Do I need to mention it?
If so, the police where I live provide a "letter of good conduct" - is this what I want? The other (and cheaper) service just states "search for record", while the I-751 instructions says that the important part is confirming no charges were filed, so I'm not sure which I should be doing here.