Genetic Technologies, Inc. assisted the State of Iowa present evidence that refuted a rape defendant’s alibi and corroborated the victim’s testimony. The defendant in this case had enlisted the help of friends and relatives who testified that he had been with them at the time of the assault. The perpetrator of this heinous and violent act was easily identified through the use of DNA profiling. The genetic evidence told a different story in that it revealed a DNA profile expected to occur at a frequency of one in 260 billion…the same profile exhibited by the defendant.
In sexual assault cases, Genetic Technologies, Inc. can work with the astute investigator or detective to process the crime scene searching for clothing items, couch cushions, or bed sheets for stains consisting of blood, semen, and/or vaginal fluid. The examining physician should collect a sexual assault kit. If the victim violently resisted the attack, she may have the perpetrator’s skin/blood beneath her fingernails. Fingernail scrapings may offer the only physical (DNA) evidence, as rape is an act of violence and seminal fluid is not always present.
A sexual assault kit contains vaginal swabs that may consist of a mixture of the suspect and victim’s DNA. The male fraction of this mixture is isolated from the female fraction by washing and removing all cellular material with the exception of the sperm heads. The male genetic profile is determined by analyzing the male fraction (sperm heads).