Technology uncovers invisible evidence

Police are using modified cameras capable of finding hidden forensic evidence such as bloodstains and gunpowder.

The cameras have been used to scan serious crime scenes for evidence invisible to the human eye, according to police online magazine Ten One.

Police photographers look at crime scenes through the LCD screen on the back of the modified camera, said Sergeant Karl Wilson, of Auckland Forensic Imaging.

"It's quick, non-destructive and very cost-effective," Wilson said.

"We've used the technology to check the inside of cars, screen homicide scenes for latent evidence and photograph studio exhibits."

The cameras had certain filters removed so they received all light, including ultraviolet and infrared, Ten One says.

This could show up hidden forensic evidence, such as bloodstains, gunpowder and inks. The photographer could create contrast to show separate substances.

Wilson said the scans would not work every time, but new approaches were worth a try to get the best possible evidence.

Another piece of technology still in the pipeline was a portable DNA analyser, which would give crime scene results in just an hour.

DNA extraction and analysis would be carried out at the crime scene, rather than having to be done in a laboratory, using the prototype developed by NEC.

ESR scientists were considering its use in New Zealand.

Fairfax Media