The recent shooting of a Dallas SWAT lieutenant on cover/containment during a drug raid serves as a reminder of the many dangers of cover/containment. Often overshadowed by its more "glamorous" entry counterpart, cover/containment is essential to successful SWAT operations, especially raids and searches.

The purpose of cover/containment is to prevent escape, and the success of the mission may very well hinge on the effectiveness of the perimeter. Desperate criminals facing the prospect of arrest often go into fight and flight (fighting their way to flight). Tight perimeters are the means to "lock in" suspects, allowing their apprehension

In concert with the surprise, shock, and speed of a SWAT action, the entry and cover/containment elements form a nearly escape-proof combination. Yet, despite its importance, cover/containment can easily be overlooked in raid and/or search planning. I'm certain most law enforcement officers can readily cite their own perimeter horror stories, where perimeters turned to disaster.

Here are a few that I am familiar with, and the lessons learned:

• During a federal fugitive search, shots were fired inside the apartment, resulting in an agent's death. Outside perimeter agents, hearing "Shots fired! Agent down!" left their positions and rushed inside to "assist." This allowed the shooter to jump from a bedroom window and escape. After a massive five-day manhunt, the suspect was finally apprehended.

Lesson learned: Hold your position until officially "secured."

• A SWAT team conducting an early morning violent felon search thought the suspect would be asleep and put all but one officer on entry. Upon entry, the "sleeping" suspect climbed out of a basement window and almost escaped. The outside officer apprehended him alone.

Lesson learned: Over-relying on surprise and putting all your eggs in one basket can backfire.

• An entry team searching for a murder suspect was confronted by multiple "noisy" occupants. In the confusion, the suspect emerged from his hiding place and literally "shot his way" through the entry team, killing one officer, and wounding several others. The suspect then kicked in the door of the adjacent apartment, escaped out a window and opened fire on the surprised outside perimeter officers who were still covering the original apartment. Days later the suspect was cornered again. This time he barricaded himself before eventually being talked out.

Lesson learned: Always watch your back. The suspect may be behind you.

• During a drug raid, the front cover/containment team (non-SWAT) broke completely down into a "snowball fight" among themselves. Luckily, no suspects escaped as a result.

Lesson learned: Obviously, these guys had their heads up their rears and endangered the raid by their reckless disregard for the mission.

• One SWAT team conducted three simultaneous drug raids on the same street, with only 11 officers. All of the officers were assigned to entry, leaving none on cover/containment. Luckily, nothing occurred on the outside.

Lesson learned: Don't leave the outside unmanned.

• A drug raid was planned where rear cover/containment approached from a street behind the building. Unfortunately, this was a multi-building project complex where all of the buildings looked exactly alike. Predictably, the rear team ended up covering the wrong building, leaving the target uncovered.

Lesson learned: Don't get fancy when approaching unfamiliar or complicated target locations.

Often, cover/containment officers are surprised when they actually see any action. But they need to be alert. Desperate suspects have been known to dive through second- and third-floor open and closed windows. Many fleeing suspects turn into Olympic athletes, leaping over tall fences at breakneck speed. Suspects very often throw contraband, from drugs to guns out of windows.

Adequate cover/concealment is usually sparse on perimeters, so use whatever's available. If no cover is available, consider positioning as close to the target as possible. This forces suspects to expose themselves, before they can see you. But test it in training first.

Other threats include vicious dogs, especially in backyards. (As I discussed in an earlier column, CO2 fire extinguishers are very effective for keeping dogs at bay.)

"Hostile" family and friends of the suspect may also attempt to force their way into the target location. Always establish a vehicle rear guard, especially in "hostile" neighborhoods where unattended police vehicles are easy targets for vandals.

In warm weather, it's common to find more suspects outside the target location, than inside. My team went on a raid once where we found 30 suspects outside. This required some entry personnel to divert to assist cover. The lesson here is that you should build flexibility into your raid/search plan in case the unexpected happens.

For many SWAT teams-especially smaller teams or larger teams conducting multiple raids-SWAT providing its own cover/containment is often a luxury. The result is that non-SWAT personnel must handle cover/containment while SWAT does the entry. Not the ideal situation, but often the only option.

Anytime SWAT and non-SWAT work together, it is essential for the SWAT raid leader to conduct a separate briefing for ALL non-SWAT personnel. And when possible, include non-SWAT raid personnel in your debriefs, even if only informally on-scene.

Always treat non-SWAT personnel with respect but be sure to establish the rules before the raid begins. Examples of these rules include: No shooting into any location where SWAT may be inside. And hold positions until secured by SWAT.

Look at successful raids and searches as the result of the "hammer and anvil" strategy. The entry element is the "hammer," and the cover/containment element is the "anvil". One without the other will result in failure. But when the "hammer and anvil" work in unison, the result is almost always success.