Why hair bleach is a murderer's best friend

2017-09-17 07:00:07

By Jeff Hecht BUDDING crime-scene investigators take note: a common household bleach can render the forensic techniques for detecting blood useless. There are two types of bleach found in household cleaning products. Chlorine-based bleaches are known to make bloodstains invisible, but applying chemicals such as luminol or phenolphthalein will still reveal the presence of haemoglobin – crucial for identifying blood – even after up to 10 washes. In contrast, oxygen bleach, which contains an oxidising agent such as hydrogen peroxide,