(NewsNation) — Questions have swirled around what led to the Jan. 7 traffic stop that led officers to allegedly beat Tyre Nichols to death in Memphis.

Five police officers were fired and charged with murder, and the specialized unit they were a part of was disbanded. Two more officers have been suspended. Also fired: two Memphis Fire Department emergency medical workers and a lieutenant. And more discipline could be coming.

Memphis Police Director Cerelyn “CJ” Davis said in an interview Friday that a “lack of supervision in this incident was a major problem.”

“When officers are working, you should have at least one supervisor for every group or squad of people,” Davis said. “Not just somebody who’s at the office doing the paperwork, somebody who’s actually embedded in that unit.”

Los Angeles Sheriff’s Department Lt. Eric Strong said supervisors are usually on about a one to five or maybe one to eight ratio, if not higher when dealing with the field such as sergeants and patrol line.

“Many departments have policies that require a supervisor to show up when a certain call goes out,” he said. “However, if this is an observation, in other words, this is something that wasn’t broadcast over the radio, and the officers make an observation, and they take police action supervisors not going to know about that. Then, you have to consider response time as well.”

Strong said those are some of the factors that would keep a supervisor from being present at the time, but supervision can’t control everything.

“I think it’s necessary and very important to understand that this starts well before them getting on the scene,” he said. “This is a supervisory issue in terms of training and accountability that was going on well before this incident.”

All of the five officers charged in the Jan. 7 incident had less than six years on the force. Many have questioned why what appeared to some like young, inexperienced officers were assigned to a special assignment.

Strong said depending on the agency, someone could “pick up quite a bit of experience,” in a matter of four or five years depending on the call volume and type of neighborhoods and cities they’re working in.

“For some of these specialized units, you want people that are young, that are energetic, that are eager to go out and do good police work. This was a failure in terms of these officers being unethical. These officers were just, at the time, the wrong people to be having in this kind of unit. I can’t say that across the board, that a five-year veteran doesn’t have the experience to do this. I think that many of them actually do.”