Question

Explain in your own words the steps taken to collect a liquid material pooled on the floor of a scene, suspected of being thrown in the face of a victim. Include documentation steps, choice of container and your request from the lab for any testing

Answer 1

Ans). Steps involved in collecting liquid sample pooled on floor:

1. The blood on floor is collected by using the cotton swabs, so different swabs are used to collect liquid on different places on the floor.For each separate blood drop, stain or smear, the investigator should use only one blood swab to collect a sample. One-by-one, use swabs to collect the blood, concentrating the blood onto each swab.
2. After concentrating the liquid in to cotton swabs (liquid is absorbed by cotton), swabs are air-dried.
3. Then the dried cotton swabs are placed/packed in a paper bag (paper envelop). Here we use paper bag as a container because cross-contamination of sample can be avoided in paper.
4. Documentation of evidence colllected in crime scene is included in case file by the investigators so that the overall work conducted during Crime scene Investigation can be easily reviewed. Documentation of evidence collected includes Quantity, physical characteristics of liquid sample.
5. Then the paper bag ontaining the sample is labelled and sealed.
6. The sample is sent to Laboratory for testing. Request is made by investigators to the laboratory for testing the sample to make particular analysis of sample like DNA analysis of sample, check whether it is human blood
7. Removal of sample (cotton swabs) from paper bag should be done carefully by using cotton tipped applicators and wearing gloves, cough and sneezing is avoided.

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