The articles referenced below contain guidance for organizations about terminations, and the need to slow down and assess the situation before terminating the employee, to prevent the potential for workplace violence.
25 Ways to Prevent Workplace Violence During Terminations
http://www.careerlab.com/art_25prevent.htm
Deadly Terminations And How To Avoid Them
https://www.irmi.com/articles/expert-commentary/deadly-terminations-and-how-to-avoid-them
Firing Violent Employees Safely
https://www.shrm.org/resourcesandtools/hr-topics/risk-management/pages/firingviolentemployeessafely.aspx
Terminating the Violent Employee
https://www.fisherphillips.com/media/publication/5359_12588_HR%202007%20Terminating%20Violent%20Employee.pdf
Planning Terminations That Involve Potentially Violent Employees
https://www.theeap.com/problems/planning-terminations-that-involve-potentially-violent-employees