Sample Collection Process

• Crime detection hair analysis begins with the collection process. At least four locks of hair are collected, typically from the back of the head. A lock of it can be used to test for drug abuse and possible presence of hypnotics and sedatives, suggests the website GTFCh. If drugs are detected in one of the lock segments, that is "good supporting evidence for the occurrence of a drug-facilitated crime," according to the website GTFCh.
  
  

DNA Testing

• An important and effective aspect of hair analysis is the ability for forensic scientists to use DNA testing. First, scientists secure DNA cells from the root of the hair. Then, utilizing microscopic analysis, a comparison can be made between hair evidence collected at the scene of the crime and from the suspected perpetrator.
  
  

More Reliable Test

• While urine analysis is still used as a valuable tool for determining the presence of certain drugs, hair analysis is by far more reliable. This test is especially useful in sexual assault crimes, where there may be concern and embarrassment with collecting a urine sample, according to the website GTFCh. In addition, if forensic scientists encounter analysis problems, a new and identical hair sample can be obtained.