Instead of the employee's immediate supervisor, consider having a manager with a higher level of authority than the employee's immediate supervisor deliver the discipline. The second management representative should be someone from human resources or someone the employee has been friendly with or admires. Do not have a co-worker attend the disciplinary meeting. Do not debate or allow the employee to negotiate another decision. Ideally, the meeting should last less than 20 minutes.
Workplace violence is a potential threat to every business.
Don't let it catch your business by surprise. Establishing preventative policies may not only minimize liability, it may prevent an occurrence.