All line-of-duty deaths are tragic, but perhaps the most devastating type of all LODDs is from "friendly fire." Simply put, blue-on-blue deaths should never happen. Yet, statistics show on average two officers die at the hands of other officers each and every year.

There have already been two so-called "friendly fire" police deaths this year. Both times, the victim officers were on duty, killed by other officers. The first in Baltimore in January, the second in Nassau County, N.Y., in March. Both officers were killed by fellow officers who didn't recognize their targets as police.

At first glance, it wouldn't appear that "friendly fire" police shootings are a SWAT problem. But SWAT officers are often involved. Geoffrey Breitkopf, the Nassau County officer killed March 12, was on duty in plain clothes with his badge displayed, but he was a Special Operations (SWAT) officer.

Normally, blue-on-blue incidents rarely involve SWAT officers. We are usually clearly marked as cops when we are on operations. But SWAT officers today are not always working in SWAT uniforms.

The reality is the vast majority of SWAT teams are part-time units, with SWAT collateral to the operators' regular assignments such as patrol and investigations. In essence, officers in these units have dual roles and are seldom in their SWAT uniforms, unless on specific "SWAT" assignments. Consequently, they usually wear the appropriate apparel for their primary assignments.

And even operators from full-time teams are not always easily identified on the job. A growing number of full-time SWAT teams work what's called "crime suppression" assignments. Depending on their agency dictates, they can be wearing anything from their SWAT BDUs, to dress blues, to plain clothes.

Virtually all LEOs everywhere are trained to have their badges prominently displayed and clearly identify and announce themselves as POLICE when working plainclothes assignments or responding off duty. However, circumstances tend to make such response and identification situational in nature.

Case in point: the 1997 North Hollywood Bank Robbery Shootout. All of us have probably seen footage of this horrific shootout, which left nearly a dozen LAPD officers wounded from the suspects' heavy-duty rifle fire. And we've all seen the footage of the LAPD SWAT officer who was working out when the call for help came in. He responded "as is" in his gym shorts. Yet there was absolutely no question in anyone's mind that he was "SWAT." That's because he had the presence of mind to don his tactical vest and helmet, which made him instantly recognizable as SWAT.

This LAPD officer isn't the only SWAT operator who was ever caught in very non-SWAT apparel when the stuff hit the fan. Years ago, a fellow SWAT sergeant of mine was also working out when he responded to an officer down SWAT assignment. With no time to change into his SWAT uniform, he arrived on scene wearing a bright red T-shirt, which is hardly an effective "camouflage" pattern.

Wearing gym clothes on a SWAT callout might be taking "plain clothes" to an extreme, but it points to the fact that SWAT officers may not always look like SWAT. The LAPD SWAT officer remedied the situation by wearing his very recognizable SWAT vest and helmet. And there's a lesson to follow in that: Always take whatever steps you can to identify yourself as a police officer when you respond out of uniform.

The reality of police-on-police incidents is for every actual tragedy, there are many close calls and a number of those close calls involve SWAT officers.

Here are a few examples from my department's close call archives:

• A tactical officer was stabbed and wounded during a deadly biker brawl. The officer was wearing his issued black leather jacket, with only his badge identifying him as police.

• A tactical officer was searching a yard for an armed suspect when confronted by an armed homeowner. The situation was defused safely. This officer was wearing an issued black leather jacket with only his badge as ID.

• During a search for the killer of a LEO, a SWAT perimeter officer heard from behind him: "Freeze." It was the homeowner who thought the officer was stealing his car. After several intense minutes of "negotiation," the homeowner eventually backed down.

• Three plainclothes tactical officers were the first responders to a report of two robbery suspects inside a bar. The officers identified themselves, then one "suspect" yelled "liquor agent," simultaneously drawing and aiming his gun directly at one officer's chest. After a very tense, several minute standoff and through the intervention of arriving uniform officers, the situation was resolved with no injury. Ultimately, the liquor agent was transferred to the other end of the state.

• Two tactical officers were accidentally shot and wounded by a detective whose shotgun discharged when he attempted to "help" the tactical officers kick open a door during a suspect search.

I'm guessing that many more agencies have their own close call archives. And it's only by some miracle that no one was shot and killed.

To the credit of law enforcement's training and professionalism, police-on-police shootings are exceedingly rare. However, that's not good enough, because one blue-on-blue death is one needless tragedy too many.

Related:

Friendly Fire: Analyzing the Problem

Friendly Fire: Identify Yourself As an Officer