Most businesses have some form of closing routine. Lock the doors, set the alarm, turn off the lights, go home. But there is a critical step that many businesses overlook entirely: verifying that no one is still inside the building before you secure it for the night.
Criminals who deliberately hide inside a business before closing — known in the security industry as “lock-ins” — represent a serious and underestimated threat. They enter during normal business hours, find a concealed spot, and wait. Once the last employee leaves and the building goes quiet, they have unrestricted access to everything inside, with no forced entry to trigger an alarm and no broken window to attract attention from the outside.
A thorough closing procedure is your defense against this tactic, and it costs nothing more than a few extra minutes at the end of the day.
How Lock-Ins Work
The premise is simple and effective. During normal business hours, a person enters your store, office, or facility just like any other visitor or customer. They may browse merchandise, sit in a waiting area, or walk the hallways as if they belong. At some point before closing, they move to a concealed location — a restroom, a storage closet, a fitting room, an unused office, a utility area — and wait.
Your team closes up for the night. Doors are locked. The alarm is set. Everyone leaves. The building appears secure. But someone is already inside, behind the perimeter you just locked down.
From that point, the intruder has time, privacy, and access. They can take their time selecting what to steal rather than grabbing what they can carry in 60 seconds. They can access areas that would normally be supervised during business hours. They can disable cameras or alarm components from the inside. And when they are ready to leave, they simply exit through a door — often triggering the alarm only as they depart with your property, long after there is anything you can do about it.
Because there is no sign of forced entry, these crimes can be more difficult to investigate and more complicated from an insurance standpoint. The question “how did they get in?” has an uncomfortable answer: you locked them in yourself.
The Closing Sweep
The solution is straightforward. Before the last person leaves and the building is secured, someone should conduct a deliberate walk-through of the entire facility. This is not a casual glance on the way to the door. It is a systematic check of every space where a person could conceivably hide.
Restrooms. This is the most common hiding spot for lock-ins because restrooms are expected to have closed, locked stalls that no one questions during business hours. Check every stall, every time.
Storage rooms and closets. Any room with a door that closes is a potential hiding spot. Open them. Look inside. If your storage areas are large enough to conceal a person behind shelving or inventory, walk through them.
Fitting rooms and changing areas. Retail businesses with fitting rooms are particularly vulnerable to lock-ins. These spaces are designed for privacy, which makes them ideal for someone who does not want to be found.
Unused offices and conference rooms. In larger facilities, rooms that are not in active use during the day can go unchecked for hours. A person sitting quietly in a dark conference room at 4:45 PM is unlikely to be noticed if no one has a reason to open that door.
Utility areas, mechanical rooms, and loading docks. These areas are often accessible from common hallways but rarely visited by most employees. They offer concealment and, in many cases, alternative exit routes.
Under furniture and behind displays. In retail environments, large displays, counters, and furniture can provide enough concealment for someone willing to wait on the floor for 30 minutes.
The sweep should follow the same route every night so that no area is accidentally skipped. Start at the farthest point from the exit and work your way toward the door, effectively pushing any potential threat ahead of you rather than leaving unchecked areas behind you.
Assign the Responsibility
A closing sweep only works if someone is specifically responsible for doing it. “Everyone should check before they leave” is not a procedure. It is a hope, and it results in everyone assuming someone else already looked.
Designate a specific person — or a specific role, such as the closing manager or shift supervisor — as the individual responsible for conducting the walk-through each night. Make it a documented step in your closing checklist, right alongside locking the doors and setting the alarm. If the person responsible is absent, a backup should be clearly assigned.
Consider adding a simple sign-off sheet or log where the designated closer initials and timestamps the completion of the sweep. This creates accountability and provides documentation that the procedure was followed in the event of an incident.
Integrate With Your Other Security Measures
A closing sweep works best when it is part of a comprehensive closing procedure that includes several related steps.
Verify all exterior doors and windows are secured. Do not assume they are locked because they were locked yesterday. Check them.
Confirm the alarm system is armed. Know which zones are active and verify that the system shows all points as secure before you leave. If a zone shows a fault, investigate it before departing.
Check that interior lights are set to their overnight configuration. If you use window coverings to conceal assets after hours, confirm they are closed.
Secure or conceal portable valuables. Laptops, cash drawers, and other high-value items should be locked away or moved out of sight before the building is closed.
Lock interior doors to sensitive areas. Even if the exterior is secured, locked interior doors add another layer of delay and difficulty for anyone who should not be inside.
When these steps are performed together as a consistent routine, they form a closing procedure that addresses multiple threat vectors in a matter of minutes.
A Few Minutes That Matter
The entire closing sweep takes five to ten minutes in most facilities. That is a small investment of time compared to the cost of a burglary that could have been prevented by opening a restroom door. The businesses that take this step seriously are the ones that do not have to explain to law enforcement or their insurance company how someone managed to steal from a building with no sign of forced entry.
Build it into your routine. Assign it to a specific person. Do it every single night without exception. It is one of the simplest and most effective security measures your business can implement.
Security Pros has helped Central Oregon businesses develop comprehensive security procedures for over 32 years. If you need help evaluating your closing procedures or overall facility security, contact us for a consultation.
