Checking for Understanding Which of the blood drops fell from a higher distance? How can you tell? A C B

Calculating impact angle: Width/Length, then take the inverse sin (sin-1).

For each blood drop, a string can be guided back to the point of origin

Bodily Fluids other than Blood

Forensic Characterization of semen Steps to testing: Locate the stain chemically- use APT test (acid phosphatase- enzyme secreted by prostate gland). Easily detected when it comes in contact with acidic solution and Fast Blue B dye. MUP can also be used as it fluoresces under UV light when in contact with AP. Microscopic examination- semen is unequivocally identified by presence of spermatozoa. Immerse stained material into water, stir & some transfer will occur. Stain & observe in microscope.

Problems- sexual crimes may be committed by males with extremely low sperm counts (oligospermia) or have no spermatozoa at all (aspermia). 3. Prostate-Specific Antigen (PSA). Used when + on APT test, but no spermatozoa. P30 is a protein also called PSA. Positively identifies human semen. 4. Link specimen to specific person- DNA testing

Collection of Rape evidence

All outer garments & undergarments carefully removed and packaged separately in paper bags. This is done while standing on clean paper sheet to catch any falling evidence such as hairs. If appropriate, bedding or object on which assault took place should be submitted for processing. In laboratory- materials are examined for presence of stains, materials cut, etc.

Rape kit procedures Medical exam should happen as soon as possible. These include: Pubic combings, pubic hair pulled for comparison, external genital swab, vaginal swabs, cervix swabs, rectal swabs, oral swabs, head hairs collected, blood sample, fingernail scrapings, all clothing collected, urine specimen.

Suspect evidence collection Collect all clothing and any other items believed to have been worn at time of assault Pubic hair combings Pulled head and pubic hair for comparison Penile swab within 24 hours of assault Blood sample or buccal swab for DNA testing

Time of assault info: Motile (living) sperm generally live 4-6 hours in vaginal cavity of living female Nonmotile sperm may be found in living female for up to 3 days after intercourse and occasionally up to 6 days later Intact sperm (with tails) are not normally found after 16 hours AP decreases and is not normally found after 48 hours P30 is not normally found after 24 hours