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Item examination, presumptive testing and DNA sampling

Forensic items are examined for biological fluids to identify material to send for DNA profiling. Watch Gabriella Mason-Buck explain more.
OK, Natsumi, now we’re going to take a look at the metal bar recovered from Nelson’s Dock. OK. If you have a look at the end here, you can see some brown material. What I want you to do is with the swab that’s on the bench is, I want you to swab that area. OK.
Like this? Perfect. Now what I’m going to do is take a piece of filter paper. I’m going to fold it into a triangle.
I’m then going to gently scrape the end of the material that you’ve just collected. OK.
I’ll place that down onto the bench, and then I’ll take the swab from you. And this is what we will send off for DNA profiling later, if there is a positive reaction for blood. OK. Now we’re going to carry out the hydrogen peroxide and Kastle-Meyer test as we did before. So taking a couple of drops of hydrogen peroxide, directly placing it onto the material that we’ve just collected.
And then I’m going to time the reaction of the Kastle-Meyer onto that location. Yes.
As you can see, the colour change has occurred very quickly. Yep. I believe that there is blood on the end of this item. So this swab that you have taken along with the swab that was recovered from Nelson’s Dock will be now taken to Federica for DNA profiling. OK.

Examine the metal bar recovered from the crime scene for biological fluids to identify material that can be send for DNA profiling.

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The Science Behind Forensic Science

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