Principles of Forensic Investigation Laboratories
Monday Wk4 30/07/18
Presumptive Tests
On the 2nd of June 2018, the owner of a pharmacist shop had discovered a window at the back of the pharmacy had been broken and the lock had been tampered with and several vials of medical had been stolen. Police were alerted and found evidence of a red substance located on the broken window, was collected for analysis. CCTV footage had identified four men who were in their late twenties were detained with suspicion of burglary. Suspects’ home was searched as police had questioned the four men. The presumption tests were done to determine the unknown uncontrolled collected samples which were discovered at the crime scene. To indicate what the samples were and if the samples were positive or negative in the results.
The chemical presumptive test procedure was followed to test the suspected drug collected from the crime scene, was to place a small amount of each controlled sample and unknown crime scene sample into a well. Which was cleaned before. We left a blank row of wells in between to avoid contamination. Few drops of Marquis reagent-controlled substance were placed in each well with the samples and one well without sample this test was repeated again to confirm results as the first test was unsuccessful. The same procedure was followed for the Mandelin reagent-controlled substances. Gloves were changed before commencement of the biological presumptive test, the procedure which tested the unknown point of en...
