&gt; Let me ask you directly: if someone were to rob a bank and never get caught, did they do something illegal?<p>No conviction, no crime.  I could, however, state that the bank was most likely robbed based on nothing more than accounting information.  There&#x27;s a crucial difference between stating that something happened and accusing a specific person of a criminal act.<p>&gt; If not, how would you express the claim that they did something against the law?<p>As a witness to an act, I would state the facts as I observed them, without passing judgment myself.  This is exactly what&#x27;s done in court.  &quot;At time X I was at location Y, and I saw a person with features Z enter the bank, pass a piece of paper to a teller, and run out of the bank shortly thereafter with what appeared to be cash.  I believe that person to be the defendant, who is sitting there (points).&quot;  The testimony of non-expert witnesses is limited to facts, not opinions.  Because for all I know, the note could have been a valid withdrawal slip, the customer may have been in a hurry, and the money was actually stolen by a teller and an accomplice who used the rushed customer&#x27;s large withdrawal as a cover (was the customer an accomplice?  I don&#x27;t know!).<p>If I were not a witness, I wouldn&#x27;t make such a claim in the first place.