Simeon Yetarian

You can participate in this random event only after completion of the Friend Request story mission and before completion of the Jewel Store Job. Unlike the other random events, this one doesn’t appear on the map. To start it, go to the Premium Deluxe Motorsport dealership.

Simeon will run away, and two men will attack the protagonist. You can beat or kill the attackers, or just leave the car shop.

You can also catch up and kill Simeon, but the game developers obviously didn’t envision such a scenario: auto aim doesn’t work, and if you hit Simeon by a car, the protagonists react as if killing an ordinary pedestrian.