Spotting true blood with infrared

US chemists have developed an analytical technique - multimode imaging - that can reveal bloodstains, which could be a boon for crime scene investigation. Detecting blood is a tough call for forensic investigators, despite the claims of TV fiction. Now, a team at the University of South Carolina has developed a replacement for the standard, but toxic, luminol test for bloodstains. The new infrared technique uses filters to detect bloodstains that have been scrubbed "clean". It is sensitive to one part in 100 of blood in water. Follow-up DNA testing can then demonstrate provenance. The same system can spot the difference between others stains caused by household bleach, rust, soda or coffee and might have industrial applications too.