Potential DNA evidence at the scene of crime
- The Blood stains, Semen, Saliva, Urine, Hair with hair root, Teeth, Sweat, Body tissues and cells.
- These samples would be obtained mainly from the window where the culprit got access into and the bed where the crime took place.
- Apart from the samples, other items would include; the knife, bed sheets, masks, gloves and clothing that might have been left behind by the culprit
- Since as it was a rape case which involved struggle, the culprit most probably left some small traces of the listed samples on the bed and the window known as touch DNA.
Ways of collection
- Some of the precautions include that need to be taken; wearing of protective gear like the gloves and making sure that the samples are free from contaminants as dust as much as possible, samples should not come into contact.
- Photographs at the crime scene of various samples and specific areas are taken clearly in all dimensions.
- Measurement of the knife and the window used by the culprit is also necessary to extract vital information such as the body size estimation of the culprit.
- Liquid elements from the crime scene like blood are taken by use of swabs, gauze pads or disinfected cotton wool, dried, put in a paper bag or dry box sealed and labeled to be taken to the laboratory. Liquid samples can also be collected with a clean syringe, Samples on the garments and the knife should be collected separately with the whole item.
- After collection of the samples, proper storage is essential as biological samples like the blood is known to bio-degrade easily. Room temperature condition is mostly recommended.