I'm going to act cold to a person I recently discovered was involved in a hit and run
Why do you want to act cold towards him? Do you know who he hit?
I don't know him nor the girl he hit. I only found out after the girl passed away from the car accident.
You should tell police if you know someone has been in a hit and run. They shouldn't just get away with it.
They're not getting away with it. I'm going to make things worse.
You did the right thing. Hit and runs are a serious crime, try to notify the authorities discretely so that they can be apprehended. You are also a valuable witness so if you have the time, you should volunteer your story to the police.