Secondary Transfer of Human Scalp Hair

Abstract

Abstract Secondary transfer of hair occurs when a person transfers hair that is not his or her own to an object, place, or other person. Since it is possible that the perpetrator of a crime may have transferred hairs picked up from previous associations, secondary transfer can affect the value of associative hair comparison evidence. Nine experiments were conducted as a preliminary attempt to obtain information on hair transfer mechanisms and the role of some of the variables involved, as well as to get a preliminary indication of the extent and importance of secondary hair transfer. Indirect hair transfer mechanisms were found to be much more common than direct transfer mechanisms. This study further showed that secondary transfer of human scalp hair can and does exist in casework situations. However, the extent of secondary transfer was found to be extremely variable. Some factors that can affect the likelihood of secondary transfer in a given situation are discussed. The persistence of human scalp hairs on clothing was found to be quite similar to the persistence of extraneous fibers on clothing.