Forensic Light Source - ALS

Applications - Security & Forensics

Forensic light - detecting traces with UV light

At a crime scene, fast and accurate detection of possible traces is of vital importance. Many biological fluids are fluorescent in nature, when such traces are illuminated with light of the right wavelength, they fluoresce and are detectable to the investigator.

There are several common ways to detect blood at the crime scene. One very easy and quick way to detect blood is to use UV light.

When to use UV light to detect blood:

• Reduce the risk of collecting unnecessary stains
• Detect blood on dark, red or violet surfaces
• Find blood stains that are concealed by paint

Reduce the risk of collecting unnecessary stains

By using ultraviolet light it is possible to do an effective and quick check for possible bloodstains. A bloodstain exposed to UV light absorbs all light of that bandwidth and does not reflect back – that is to say, it does not fluoresce in any way. Thus the stain will appear black under UV. Although not a conclusive test for blood, it is an effective presumptive test and can often eliminate the unnecessary collection of stains that appear to be blood are actually from another source.

Dark surfaces
The UV light source is also effective for providing sufficient contrast of bloodstains that are found on red- or violet-colored objects. Such stains often fade into the background so well that it is impossible to photograph them. Ultraviolet light often provides sufficient contrast between the background and stain to allow the stains to be visualized in a photograph.

Blood concealed by paint

It is not uncommon that a perpetrator of a crime tries to get rid of potentially incriminating evidence. This may include painting over areas that have been exposed to blood. To the naked human eye it is next to impossible to see that a blood stain has been painted over. By using ultraviolet light however, it is possible to detect blood stains that have been concealed by paint.

Crime Applications for UV

UV & Blood

UV & Body Fluids

SEMEN | URINE | SWEAT | SALIVA

Detecting body fluids at the crime scene is a delegate task. Using a UV light lamp however makes the job easier.

When to use UV light to detect body fluids:

Mark up the crime scene

Most stains from body fluids can be seen when using a high intensity UV light. That is to say that most body fluids have some fluorescent nature or reveal themselves in a special way when illuminated with UV light. In most cases it is not possible to see such stains otherwise. The most effective way of using the UV lamp is to use it to ‘mark’ the crime scene. In other words, you mark all stains that could be useful ‘traces’. When using an intense UV light it is also possible to see things at a distance that otherwise would be nearly impossible to see. While the UV light cannot confirm exactly what sort of stain you are looking at, it does indicate where the stains or body fluids are. This makes it possible to then take samples or perform further investigation.

Dark textiles

The high intensity UV light is a superb complement to more advanced Alternative Light Sources due to the fact that ALS’s often have limitations in finding body fluids on very dark textiles. High intensity UV light is being used for example to examine the interior of black coloured ‘robber’ masks, and to illuminate the sweat seen on the inside of these.

What body fluids are fluorescent by nature?

• Semen (DNA)
• Vaginal secretion (DNA)
• Urine (DNA if it contains blood or other body fluid)
• Sweat (DNA)
• Saliva (DNA)

Semen

Semen is very fluorescent by nature and the fluorescence can be observed on dark as well as light textiles when illuminated  with an intense UV light, without the need for using coloured goggles.

Vaginal secretion

Vaginal fluid is very hard to detect at all times, as it has a very weak fluorescence.

 Forensic,Crime & Security
Alternate Light Sources (ALS) .

An intensely powerful ALS lamp with a wide light beam and interchangeable filters. The TrAc Finder is made up of a crime kit plus a portable UV lamp from the Labino “TrAc” series (lamp sold separately yet delivered together in case and with clear protection filter already mounted). The crime kit contains: 4 interchangeable forensic filters; 3 coloured goggles, each in its own protective pouch and 1 rugged professional carrying case. Case interior custom designed to fit model of lamp chosen. Each filter is enclosed in a filter case that easily snaps on and off the UV lamp. Forensic filters: UV Crime Filter (wavelength 310-400 nm, peaks at 365 nm); General Crime Filter (wavelength 400-525 nm); Blue Crime Filter (wavelength 415-485 nm); Green Crime Filter (wavelength 485-530 nm). Forensic goggles: Yellow, orange, and red. Lightweight with top and side-shield protection. Universal fit can be worn with most prescription glasses. Professional carrying case: outer case of durable black polypropylene. Foam interior. IP65 classified.

The Astra Torch is a cordless battery operated torch light based on the latest LED technology designed especially for crime, security and forensic use.
The Astra Torch offers six (6) different coloured heads and 1 UV head and you are free to combine your own unique combination of heads - all kits include a UV light head and then you add as many coloured heads as you like.

Semen

Urine

Saliva

UV & Finger Prints

COLLECTING FINGERPRINTS

There are several methods of gathering fingerprints, and fluorescent powder is used for some of them. Such powder is used in combination with ultraviolet light and can be used on both nonporous smooth and rough surfaces.

Nonporous smooth surfaces:
• Painted or varnished surfaces
• Glass or Plexiglas
• Most plastics

Nonporous rough surfaces:
• Vinyl
• Leather
• Textured countertops
• Textured surfaces

Use fluorescent powder and UV light when:
• The surface is dark, patterned or spackled
• The fingerprint is very weak
• The surface is not to be damaged by carbon
• The possible DNA on the stain is not to be damaged by carbon or other powders

Dark, patterned or spackled surfaces
Putting dark powder on a dark patterned or speckled surface makes it very hard to see the fingerprint. By developing the print with fluorescent powder and a brush, and illuminating it with UV, the fingerprint glows and is easy to photograph. This method is very successful on beer cans for example.

Weak fingerprints
Fluorescent powder is very ‘delicate’ compared to common powders used for fingerprints. It is therefore very useful when trying to detect weak prints. If you develop the print with a very small amount of fluorescent powder (and brush) and  lluminate it with a UV light, the fingerprint will glow and become therefore easy to photograph.

Avoid damaging surface with carbon
If you are going to develop a fingerprint on a surface that you do not want to damage with carbon – i.e. a computer made of light plastic – fluorescent powder is highly recommended. Use fluorescent powder and a brush, and illuminate the print with UV. You need only use a very small amount of fluorescent powder to achieve results, which makes it useful on areas you can’t clean, like the inside of a computer for example.

UV & Fire Investigation

How is UV light used in arson investigations?
Arson investigators use ultraviolet light as a simple, reliable and cost effective method of arson detection. Ultraviolet light is used to detect information that is otherwise invisible to the human eye and to uncover valuable information which can be used to solve a fire investigation.

UV light is used to:
• Identify the presence of accelerants
• Identify pour patterns

Accelerants
UV light not only assists in identifying the presence of accelerants ( a substance that accelerates the spread of fire or makes a fire more intense ) , but also in rapidly locating accelerant residues, and assisting in locating the point of origin of the fire. The color which accelerants glow is affected by heat exposure. The longer an accelerant is exposed to heat (i.e. the origin), the more differentiated its fluorescence color will be from other less exposed areas. Evidence of accelerants gets absorbed in a fire and is therefore almost always invisible to the naked eye. The area tarnished by accelerants however is easily discernible under UV light.

Hydrocarbons
Volatile hydrocarbons such as gasoline, kerosene and other petroleum fractions such as benzene, acetone, grease, lard, vegetable oils, paints, etc fluoresce when exposed to UV light. By using UV light, investigators can accurately identify locations where samples should be collected for further laboratory analysis. UV light can also be helpful in locating fragments of incendiary devices since explosive wrappings are frequently fluorescent. Samples collected in cans and plastic evidence bags can be heated in warm water to form condensation. The latent accelerant residue rises to the surface and this can be seen under UV light.

Pour patterns
UV light has been used to identify pour patterns, the shape of an accelerant container and pour trails leading back to containers. UV light will indicate accelerant long after its odor is discernable. Masking an accelerant will not prevent its UV detection. Accelerant on skin or clothing will fluoresce as well.

PROPERTY MARKING AS A CRIME COUNTERMEASURE
Police routinely use UV light to detect, identify and return stolen property that has been marked with fluorescent ink. By using a UV fluorescent marking pen, valuables can be discretely marked with important details such as a name, initials, phone number, case number, date or other information. Police also mark weapons, plastic baggies of narcotics or electronics used in sting operations using this method. Such ink is invisible to the naked eye and is only revealed when illuminated with UV light . In case of burglary, the owner of a recovered, stolen item which has been marked in this way can be traced simply by using an ultraviolet lamp. Other inks work in a near opposite way by absorbing ultraviolet light. When they are used on fluorescent paper, the written-on areas fluoresce less than the surrounding paper areas when under an ultraviolet lamp. Invisible ink pens can be used on most glass, plastic, wood, paper, cloth, and metal surfaces. By illuminating the marked surface with UV light, the marks become clearly visible to police, detectives and pawn shop owners.

INTERCEPTION OF SECRET MESSAGES
Successful use of invisible ink depends on not arousing suspicion. Telltale signs of invisible ink, such as scratches from a sharp pen, roughness or changed reflectivity of the paper can be obvious to a careful observer who simply makes use of strong light, a magnifying glass and their nose. Also, key words in the visible letter, such as 'red cabbage' or 'heat', in an odd context may alert a censor to the use of invisible ink. By using ultraviolet light, messages can be quickly screened for invisible ink and also read without first permanently developing the invisible ink. Thus, if a censor uses this method to intercept messages, he may then let the letter be sent to the intended recipient who will be unaware that the secret message has already been intercepted by a third party. A "screening station" could theoretically involve visual and olfactory inspection, an examination under ultraviolet light and then the heating of all objects in an oven before finally trying exposure to iodine fumes.

UV & Invisible Ink

Advantages of UV light compared to canine or mechanical ‘sniffers’
• Use of UV light is not affected by wind conditions.
• The ‘sniffer’ indicates a general area of saturation yet does not detect specific infected areas. This makes pour pattern sampling difficult. UV light detects specific areas.
• The ‘sniffer’ is effective only two to three days after saturation. UV lamps have been proven to effectively fluoresce samples up to two months after an incident.
• After a lengthy hot fire, the odors of accelerants have usually disappeared.

ENVIRONMENTAL INVESTIGATIONS
Illegal dumping
UV light can assist in environmental investigations by indicating the presence of hydrocarbons on land and in water. Illegal dumping has been traced using this technique. Trace dyes can be used along with UV light, and some radioactive substances fluoresce as well.

COCAINE | AMPHETAMINE | ECSTACY
Some narcotics such as amphetamine, cocaine and certain MDMA tablets are clearly fluorescent when illuminated with UV light. Even minute amounts of certain narcotics can be readily visible when illuminated with UV, making the investigators work much easier when, for example, performing a house search for suspected narcotics. Powder and powder residue which remains on clothing, hands, tables, kitchen sinks, balances and other tools, and which is not normally visible in normal light, becomes highly visible with the use of ultraviolet light.

Fluorescent narcotics
• Cocaine
• Amphetamine
• MDMA tablets (including some but not all Ecstasy tablets)

Cocaine
Cocaine having a purity of at least 87 % fluoresces clearly when illuminated with UV light.

Amphetamine
Some amphetamine having a purity of 78 % (i.e. of Dutch, Baltic or Polish origin) are clearly fluorescent when illuminated with UV light. Even small amounts of amphetamine are easy detectable because of their fluorescent nature.

MDMA tablets
Some MDMA tablets (i.e. Ecstasy with four-leaf clover logotypes) are clearly fluorescent with UV. Even small fragments are easily visible as they fluoresce intensively.

UV & Narcotics

The Labino Astra Torch Light Crime Kit
High Performance ALS Alternative Light Source / Alternate Light Source LED Torch / Flashlight - For Forensic & Crime applications.

The Labino TrAc Finder Crime Kit
Very High Performance Alternative Light Source / Alternate Light Source (ALS) - For Forensic & Crime applications.

Applications
for the Labino Alternative Light Sources (ALS)
Trac Finder, Astra Torch & Nova Torches

The Labino TrAc Finder Crime Kit
Very High Performance Alternative Light Source / Alternate Light Source (ALS) - For Forensic & Crime applications.

The Labino Astra Torch Light Crime Kit
High Performance Alternative Light Source / Alternate Light Source - ALS LED Torch / Flashlight - For Forensic & Crime applications.

Advanced NDT also offers many other UV lights in a variety of styles from Labino mains powered, Labino battery powered , Labino mains and battery operated and the very popular pocket sized UV-A LED blacklight UV torches.

ADVANCED NDT LIMITED,
Orchard House, Orchard Close, Severn Stoke, Worcester, UK    WR8 9JJ
Telephone: 44 (0) 1905 371460         ***  Fax:   44 (0) 1905 371477
E-Mail:  sales@advanced-ndt.co.uk ***  Website:   www.advanced-ndt.co.uk

The Labino Nova Torch Light Crime Kit
High Performance Alternative Light Source / Alternate Light Source - ALS LED Torches / Flashlights - For Forensic & Crime applications.

The Labino Nova Torch Light
High Performance ALS (Alternative Light Source / Alternate Light Source) LED Torches / Flashlights - For Forensic & Crime applications.