Breakthrough in investigating crime scene

New research can help build cameras that can detect blood stains as well as when they appear, promising to revolutionize the field of criminal investigations.

Samples of blood and other fluids in the field are the most commonly used evidence in the process of searching for murderers who cause crime in murders. And this is not new. People who love the popular TV series CSI: Investigating crime scene produced by the US must be too familiar with the process of collecting blood stains at the scene. First, forensic experts had to spray or sprinkle chemicals on surfaces they hoped for the presence of blood stains. Then, they observed the reaction between the specimen collected in the solution, to find the iron element in the hemoglobin.

However, if no evidence is collected, it is likely that investigators cannot point out exactly who caused the crime. For example, in a murder investigation in 1993, police failed to find evidence to suspend suspects in the murder of Stephen Lawrence, 18. Over many years of hard investigation, in 2011 the prosecutors hold in their hands the identity of the murderer (thanks to the blood stain on the collar), and 2 of the original 5 suspects have to pay offense in in 2012. In the Damilola Taylor male student murder in 2000, experts neglected the blood stains on the sneakers of one of the boys who killed the boy.

Collecting blood samples at the scene is still based on old techniques - (Photo: Science Photo Library)

According to Dr. Meez Islam of Teesside University (UK), this is because forensic experts often face serious problems when it is necessary to identify blood stains. That is they still have to apply analytical methods that have been used for centuries.'Normally, at the crime scene, the blood will never show up easily for you to see. The blood on the dark surface is even more difficult to see, and there are traces that cannot be detected with the naked eye ' , the Independent quoted Dr. Islam.

The new technology, which will be introduced at Manchester Forensic Science Conference next month, uses liquid crystal filtration equipment , capable of delivering results almost immediately. This filter works by isolating different color wavelength ranges, so it can detect blood stains in similar impurities, or hide in difficult places like clothes, carpets, red furniture. Because blood changes color over time, from bright red to muddy brown at specific times, the device can determine the 'age' of the blood spot accurately. Experts say that the technology could also be applied to other fluids, including sweat, saliva, and semen, to speed up conviction in sexual abuse cases.

Based on the new technology, the Teesside University team (UK) has built a prototype camera capable of scanning the spectrum of hemoglobin, making investigation faster and more accurate. Experimental results show that within a day, this camera can specify the time of blood samples collected a month earlier. The next step, Dr. Islam said he needed £ 100,000 if he wanted to make a device version that could be used in practice.