Skip to 0 minutes and 4 secondsOK, 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.

Skip to 0 minutes and 28 secondsLike 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.

Skip to 0 minutes and 45 secondsI'm then going to gently scrape the end of the material that you've just collected. OK.

Skip to 0 minutes and 53 secondsI'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.

Skip to 1 minute and 31 secondsAnd then I'm going to time the reaction of the Kastle-Meyer onto that location. Yes.

Skip to 1 minute and 49 secondsAs 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.

Item examination, presumptive testing and DNA sampling

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

King's College London

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