I want to report my friend's friend for drunk driving
Do you have a specific incident to report?
She killed a lot of people and wrecked a lot of lives.
It may be a better idea to allow the police to handle this one on their own. It may be disruptive to get in their way when they are attempting to solve a crime.
It's time to show people what happens in these situations. I think it will be a big deal and she could have hurt me or my friends.
It is a terrible tragedy that occurred here, but the police will already be aware of the incident.  However, if you can present some evidence that the driver was drunk at the time, you should report that to the authorities.  You might be able to ensure that the victims get some justice.