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Serology in Practice

Serology in Practice. Sexual Crimes. Characteristics of Semen. Search for semen includes corpse, victim, undergarments, bed sheets, mattresses, carpeting, flooring, etc. Stain location- Often visible as stiff crusty spot (s). Identifying a semen stain. Acid phosphotase color test-

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Serology in Practice

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  1. Serology in Practice Sexual Crimes

  2. Characteristics of Semen • Search for semen includes corpse, victim, undergarments, bed sheets, mattresses, carpeting, flooring, etc. • Stain location- • Often visible as stiff crusty spot (s)

  3. Identifying a semen stain • Acid phosphotase color test- • Acid phosphotase is an enzyme found in the prostate gland • If found, an acidic solution of sodium alpha napthyphosphotase and fast blue dye produces a purple color • Presumptive test

  4. Identification • 4-methyl umbelliferyl phosphate (MUP)- • Will fluoresce under UV light • Reaction time of less than 30 seconds is evident of strong semen concentration • Fruit juices, cauliflower, and watermelon produce false positives

  5. Identification • Microscope • Immerse stain in small amount of water and view under microscope • Presence of spermatozoa is proof of semen sample • 2 key terms • Oligospermia- low sperm count • Aspermia- absence of sperm

  6. Identification • If no spermatozoa • Run p30 (specific antigen (PSA)) test • Combining antibody30 with electrical charge causes a visible line between antigen and antibody • P30 is unique to seminal fluid

  7. Positive Test, then what… • Once semen test produces positive results, a link is made to individual through DNA

  8. Sperm Facts • Motile Sperm • Generally survives 4-6 hours in the vaginal cavity • Non-motile Sperm • Can be found up to 3-6 days • Intact sperm with tails not normally found after 16 hours • Important to find out time of rape and time intercourse

  9. Sperm Facts • Important to rule out consensual partner through buccal (mouth) swab and blood sample • Semen is resilient • Even after washing clothes, sheets, linens, etc. there could still be traces of spermatozoa and PSA • Just ask President Clinton about Monica’s Dress…

  10. Dealing with Rape • What is rape? • The unapproved sexual advances upon a person • In order to be classified as rape: • Must be actual penetration • Use of force by assailant • Lack of mutual consent

  11. Facts on Rape • Not stopping having sex when indicated by your partner despite previous consented sex is rape. • Pushing sex when your partner does not want it is rape • If you get a person inebriated, then perform sexual intercourse it is rape • If you don’t get a person drunk/high and know they are, but perform intercourse, it is rape • If you don’t get a person drunk/high and don’t know they are, but still perform intercourse, it is rape • If you are also drunk or high and have sex you have committed rape.

  12. Types of Rape • Marital Rape: forcible, unwanted sex in a marriage • Statutory Rape: sex with a minor under the age of consent, even if the minor agrees to the act • Blitz Rape: an unexpected sexual assault by a total stranger • Acquaintance Rape: rape committed by someone barely known • Incest: the rape of a child by an elder relative • Group Rape: a group of people participate in the rape of a single individual • Gray Rape: a victim’s word against the assailant, there is no other evidence

  13. Dealing with Rape • Trauma goes beyond physical discomfort • May cause long lasting psychological trauma • Rape is a heinous crime that although it involves sex, is about aggression and humiliation

  14. Dealing with Rape • Rape is often accompanied by homicide, either as part of the violent act or attempt to prevent getting caught • Rape is often part of a serial killer’s homicide • Particularly when killer is sexually sadistic • Photo is John Wayne Gacy

  15. The Rape Exam • Should be completed as soon as possible • Unfortunately, most victims wait days, months, or even years before even reporting the crime

  16. Rape Evidence • Semen- presence indicates sex, but not rape • Bruises, scars, abrasions- proves violent event, but not rape • Transfer of physical evidence- blood, semen, hairs, and fibers make a good case for rape

  17. Collection of Evidence • ALL outer and undergarments from the involved parties • In separate paper bags, not plastic • Place clean bed sheet on the floor and lay a clean paper sheet over it • Victim removes shoes before her standing on paper • Have victim disrobe while standing on paper, this allows for foreign material to collect on the paper

  18. Collection of Evidence • Collectors should wear disposable latex gloves to prevent contamination • Victim should undergo a medical examination • Evidence and medical results provide support for rape case

  19. Can a male be raped by a female? • By definition of rape, yes he can. • In order for a male to be raped by a female, the female must first do something to sexually arouse the male. • This is followed by forced penetration (the definition of rape).

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