Scientists Can Now Determine What Time Biological Evidence Was Left At Crime Scene
Tuesday, May 11, 2010
According to Dr. Manfred Kayser, head of the Forensic Molecular Biology department at Erasmus Medical Center in Rotterdam, scientists just need a small amount of blood or saliva to be able to determine at what time this biological material was left at a crime scene. Researchers at Erasmus University have established that the natural occurring hormones, melatonin and cortisol that are found in blood and saliva can be used like a clock. During the night there is a high concentration of melatonin in the human body which slowly disappears from the body during the day. In contrast, the highest concentration of the hormone cortisol is found in people in the early morning right after the person awakes and slowly disappears as the day progresses. By testing the concentrations of these two hormones found in blood or saliva researchers can determine when the sample was left. This can help law enforcement check the alibi of suspects and determine with greater accuracy when a crime was committed.
Read the original Dutch article here.
Video interview in English with Dr. Manfred Kayser is available here.