Can we ban an ex-employee from our parking lot?

Q: “An ex-employee (terminated in September 2021) was in the parking lot of our business May 2022.  The individual decided to park his car in the middle of the parking lot (including blocking one car).  Employees leaving were honking and maneuvering to try to pass this vehicle.  The ex-employee was talking with one of our current employees outside the car not willing to move.  The employee's car, which this person directly blocked, needed to leave and they asked this person to move the car to which the response was "You have plenty of room.” This happened repeatedly until our employee screamed at the person (using profanity) and the ex-employee finally moved the car. The employee was very upset and reported the matter the next day.  We would like to issue a letter to the ex-employee informing them they cannot come onto the premises (including the parking lot) and explaining they created a negative situation for our team members and that if they show up, they are trespassing and we will notify the authorities. Can we do that?” - Lorraine