Well for one the guy whose car it was technically saw it happen too and I’m pretty sure he called the police. I don’t think I would have much to add. Plus I’m pretty sure they were arresting the people involved as I was leaving. The mall also has security cameras.
I did look it up btw and it is not required by law to report what I saw. There are certain cases where it is (like child abuse) but the type of crime in this scenario is not one of those types.
I totally respect your decisions to stay out of it. In this day and age, you can never be too careful. I was in a slightly similar situation, and the police wanted to talk to me, because I thought I was helping a friend. They asked me for details, but I politly requested to refrain from giving certain details.
The cop told me I was obstructing justice, and I said I would like to help you, but I don't want my friends ex not getting a job for the next 5 years, because of a criminal record. I told the cop, I've seen a good friend of mine struggle with employment in his field, because of one mistake. The cop looked at me, and said you're a person with integrity, don't worry about my request.
If I were asked any info from a cop, I would have provided everything I knew. I think that is a slightly different situation though than needing to volunteer it without them asking.