• Suspicious White Powders

^{Suspicious white powder}

For purposes of investigation and prosecution, the lab identifies suspicious white powders used in anthrax hoaxes. White powders may be innocuous household products or toxic materials. 

• Corrosive and Toxic Substances



Corrosive liquids such as strong mineral acids, organic acids, alkalis, oxidising and bleaching agents are encountered in cases of grievous hurt.

• Noxious Substances

 
^{Debris from device that generated a noxious gas (right)}

Pepper sprays, common spices (chilli and pepper), riot gas agents, formaldehyde and other noxious substances and chemical irritants may be used in assault, robbery or mischief cases. Traces of these substances on clothes, skin and other surfaces can be identified.

• Industrial Materials and Toxic Industrial Chemicals (TIC)

Industrial materials and toxic chemicals can have extremely serious health effects on individuals and the environments when released either accidentally or deliberately. Criminalistics Laboratory has the capabilities to identify a wide range of such materials and chemicals, which may be encountered in hazmat exposures, industrial incidents and criminal activities.

Forensic Chemistry and Physics Laboratory identifies the chemical composition of unknown solids, liquids, aerosols and gases.

Solid

• Adhesives
• Powders
• Paper products
• Wood chips
• Oxides, salts, metals and etc.

 
Liquids

• Detergents
• Organic solvents
• Petroleum products
• Adulterated solutions

 
Gases

• Permanent gases : hydrogen, helium, oxygen, nitrogen & carbon monoxide
• Light hydrocarbons : methane, ethane, propane, iso-butane, n-butane, LPG gases, etc

^{Multi-layered paint}

Paint is transferred in the form of chips, flakes or smears between surfaces that come into forceful physical contact, as in collisions and the application of a tool on a surface. Multi-layered paint chips can provide strong evidence associating two objects. Paint transfers may be found on vehicles, machines, boats, walls, doors, windows, lane markings, footwear, and tools such as screw-drivers and pliers.

 
^{Acrylic fibres (left); cross section of carpet fibre (right)}

Fibres on clothes, seat covers, upholstery, carpets and other fabrics are easily transferred from one source to another. Fibre evidence is encountered in crimes involving close physical contact such as assaults, burglaries, kidnappings, hit-and-run collisions, rapes and stabbings. Examinations include: identification of fibre class and subclass, linking transferred fibres to their article of origin, physical matching of textile fragments to torn fabrics, linking a fabric weave impression on a vehicle to a hit-and-run victim, comparison of yarns, threads and buttons, and distinguishing between human and animal hairs.

^{Plastic vehicle lamp cover}

Polymeric motor vehicle trim, rubber bumpers or plastic lens covers can be associated to plastic remaining on property or left on the road in a hit-and-run case. Wire insulation, plastic bags and miscellaneous plastics can be compared with known sources.

^{Edge of broken glass with conchoidal fractures}

Broken windows, glass panels, vehicle glasses, bottles and other glass objects are encountered in break-ins, murders, hit-and-run accidents, vandalism of vehicles and other crimes. Microscopic glass particles found on a person or embedded in footwear soles can link the suspect to a broken glass pane. Glass fracture examinations reveal the cause of breakage, the direction of breaking force by an object; and in shooting cases, the sequence of bullet shots. 

 
^{Is this diamond? (left); solid gold or plated? (right)}

The chemical composition of metals, gemstones and jewellery may need to be ascertained in cases of robbery, alleged theft or cheating. Fraud may require the determination of the quality and quantity of precious metal in the article purported to be valuable. Chemical analysis of the surface and interior of jewellery items reveals whether the items are homogeneous or merely coated. Metal fragments, filings and smears on cutting tools (saws, drill bits, cutters) can be matched to damaged metal objects such as padlocks, gates and grilles. 

^{Soil materials}

Soil present on the footwear or clothes of a suspect, or on the tyres or floor mats of a suspect's vehicle may be matched to soil at the crime scene. Building materials such as concrete, cement, caulks, brick, plaster, wood particles and paint may be found on the clothing of burglary suspects and on tools used for the break-in. Insulation material may link a burglar to a safe.