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Search Engines

Conducting a thorough head-to-toe search requires as intrusive a probing as garments will allow.

Author Dean Scoville Headshot

When it comes to dealing with the usual suspects, we cops lack Superman's x-ray vision, and most of us are bereft of Jeane Dixon's psychic powers. To compensate, our B.S. detectors generally function pretty well, and we can always rely on Terry v. Ohio to justify our cursory pat-down searches of those who may not have our best interests at heart.

But despite its appellation, there is nothing "cursory" about a good protective search. Conducting a thorough head-to-toe search requires as intrusive a probing as garments will allow. Beyond the pat-down lies the rub, the strip search, the visual body search, the cavity search, and the ever-popular digital body search. With each succeeding level of intrusion, the greater the need for legal justification.

Once the legal justifications are in order, other considerations need to be addressed. Can the search be conducted in a safe manner? For example, is your center of gravity compromised by the stature of the person being searched?

Also, there are sanitary considerations. No cop likes the thought of dealing with a detainee whose hygiene is as suspect as his character. Going "hands-on" with a subject who's vomited, urinated, defecated, or otherwise done nasty things to his person is enough to diminish any cop's vigilant enthusiasm.

Add to these factors a desire to avoid embarrassment at the possibility of missing something-as much as the possibility of getting killed if you do-and it's no wonder that your need to maximize security while minimizing impositions can, at times, seem daunting.

It needn't be that way.

When it comes to the least intrusive means of assuaging fears and placating modesties, the answer for many agencies is the metal detector. Already a fixture in many of the country's schools, courts, and airports, there is an increased demand within the private and public sectors for its use. In these days of school snipings, mass murders, workplace shootings, and terrorist attacks, this is known as preventive maintenance.

The metal detector can be not only a less intrusive means for you to conduct searches, but also a more expedient one. It can obviate the need for a male officer to wait for a female peer to respond for a pat-down search of a female subject. And besides being an equalizer in cross-gender searches, metal detectors give you a safe and efficient means of completing investigative detentions without feeling as vulnerable as you might otherwise.

Metal detectors can be used to locate everything from knives, to guns, to bombs (many have metal fuses) and, with more sensitive models, razor blades and hypodermic needles. In the absence of a canine, a metal detector can even assist in locating discarded firearms and burglary tools in grass and weeds. Ironically, despite their effectiveness, metal detectors require fewer legal justifications than a Terry pat-down.

Magnetic Resonance

Metal detectors work by transmitting low intensity magnetic fields that react when they come into contact with metal objects. The disruption of the magnetic waves causes a ripple effect around the metal surface. Similar to throwing a rock into a pond, the ripples emanate outward and are then detected by the metal detector's receiver. Using this information, the metal detector can determine the general size, shape, and location of the metal object.

When it comes to design and purpose, there are two primary types of metal detectors: the stationary and the portable. Between them, everything between Mohammed and the Mountain is covered.

The inducements for a department to purchase metal detectors are myriad. The Roseville (Mich.) Police Department decided to equip every patrol car with a handheld metal detector in response to the recent death of Warren (Mich.) Detective Sgt. Chris Wouters. Roseville Councilman Jim Zelmanski suggested each scout car in Roseville get a detector in response to the slaying of Wouters, who died after a suspect sneaked a handgun into the police lockup and shot him during a struggle.


When evaluating a department's need for metal detectors, the carpenter's maxim "the right tool for the right job" comes to mind.

To screen large numbers of persons at points of entry, stationary walk-through detectors are the tool of choice. They can be found in courtrooms and airports.

Once a set of keys, a belt buckle, and loose change have been secured, a non-threatening visitor can pass through a detection portal without further delay. Similarly, parcels can be scanned for weapons. And walk-through detectors are certainly less apt to offend one's sense of modesty than the anatomically defining x-ray machines found in airports.

Stationary detectors run the gamut from portals to chairs and can be housed in everything from station lobbies to the jails (where privacy issues are a lesser concern). In fact, the Body Orifice Security Scanner (B.O.S.S.) produced by Ranger Security was instrumental in helping solve a recent murder. The victim's missing jewelry was located during a routine security screening of a prisoner using this chair-like apparatus, which provides a non-intrusive way to scan all bodily orifices. Beyond that, 1,500 stabbings and slashings occurred in New York City's jails in 1990. Last year this figure dropped to 229 largely because of screenings by metal detectors.

The most effective stationary detectors utilize multiple zone sensors, can detect a wide variety of metal types, provide responses that are commensurate with the size and shape of the object, and are easy to maintain and use.

Walk-through detectors must also be able to handle the speed and volume of traffic while maintaining their metal sensing effectiveness. The scan display should also be easily readable from several feet away, and should clearly indicate the location and relative size of the object.

It's important to avoid using walk-through detectors that utilize infrared beams that trigger activation, as these are easily bypassed. Instead, opt for continuously active detectors and those that can easily be programmed to compensate for background metals in floors or surrounding areas.

Magic Wands

When a walk-through detector fails to clear a visitor, sometimes a portable detector is used. Handheld detectors also have wide applications in the field. A portable metal detector allows you to conduct a quick and effective inspection when a more thorough search may eventually be required, but is momentarily less practical.

The best of these magic wands are capable of locating a hype's needle (although protective gloves are still recommended). The ideal handheld scanner is lightweight, but rugged. The Model 1000 by Ranger Security, the Metal-Tec 1400 by Torfino Enterprises, the Super Scanner by Garrett Metal Detectors, the Seeker One by Mogul Co., and the Hand Wand by Control Screening are excellent examples.[PAGEBREAK]

Most handheld metal detectors range in size from a cricket bat to an ice cream bar, but Garrett's Enforcer G-2 and the Seeker One by Mogul Co. are so compact and lightweight that they will fit into a shirt pocket. These little wonders can find even the smallest weapon, yet will easily fit in the palm of your hand.

Handhelds use a combination of audio signals, visual alarms, and silent vibration to alert the user when metal objects are encountered. The intensity of each response indicates the relative size of the object. As with the stationary units, the best handheld scanners can be easily programmed to compensate for background metals in floors, surrounding areas, and even on the operator's person. In order to meet the unique requirements of field work, handheld detectors should also feature an automatic battery check and easy battery installation.

Typical handheld models can detect objects at the following distances:

  • Medium-size pistols from a distance of 9 inches
  • Large pocket knives from up to 6 inches
  • Razor blades from up to 3 inches
  •  Hatpins from up to 1 inch

Whether a stationary or portable detector is used, it is imperative that the operating officers receive extensive training on the specific equipment that they will be using. It is also highly advisable that the detector either meet or exceed FAA standards.

When choosing a detector for police use, there are four factors to be considered: effectiveness, ease of use, cost, and officer and public safety.

Vendors should provide information about warranties, the convenience and timeliness of repair services, and the availability of loaner replacements during repair. As with any product, caveat emptor. While some officers sing the praise of a particular product line, others strongly caution against the purchase of certain non-FAA-approved products.

Non-Metallic Weapons

Despite their effectiveness in finding potentially lethal weapons, metal detectors are no panacea. Some devices are less dependable than others, and none of them are apt to hit on a drug (depending on what the stuff's been cut with) or silicon-edged weapons.

The primary problem is that there is a growing array of nonmetallic weapons, ranging from ceramic knives to plastic guns that can be tucked underneath jackets and smuggled past metal detectors. There are even 9mm semi-automatic weapons that can now be easily altered to go through a metal detector once certain metal parts have been replaced with ceramics and plastics.

As with the advent of every better mouse trap, some enterprising soul is always working to come up with the better mouse.

That is why security measures often entail use of canines and imaging technology to supplement metal detectors.

Experts say that the road to creating a metal detector replacement could still be a long and arduous one. One new technology uses millimeter wave imaging to detect radiation emanating from a person's body, displaying a clear outline around any object that stands between the body and the detector.

Engineers say, however, that the primary advantage of the millimeter-wave system may also be its weakness. The technology's ability to see through clothing and build a crisp image may create privacy issues among the public.

In addition to the privacy issue, engineers still need to deal with other inherent problems, including cost. While stationary metal detectors can run about $5,000, experts believe that millimeter-wave systems will not be available for less than $50,000 apiece-and quite probably will be closer to $100,000.

Ultimately, aviation experts believe that real security will require far more than millimeter-wave detection systems. Some believe that airports will need to look beyond the weapon and focus on the person as well. By using such tools as biometric and physiometric profiling, officials hope to do on-the-spot background checks and look for signs of unusual and/or nervous behavior.

Such extreme measures might one day be necessary, but whether such techniques can be employed may ultimately depend on the will of society.

Still, for cost effectiveness and practical security, law enforcement can do a lot worse than the metal detector when looking for that elusive and lethal "needle" in the haystack.

For more information on weapons detector products contact the following companies:
Control Screening
Ranger Security
Torfino Enterprises

Sgt. Dean Scoville is a patrol supervisor for the Los Angeles County Sheriff's Department and a longtime, regular contributor to POLICE. He can be reached at

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