Skip to 0 minutes and 16 secondsOK, Natsumi. I've asked for these two items in particular to be brought to my table because I want to show you how crucial these could be to the investigation. OK, now, what we're trying to do is identify a suspect, link these items - or link the suspect as well - to our deceased and to the offence. OK. What we have here is the metal bar. Yes. We recovered it some way away from the body. But we believe it to be the murder weapon. Yes. It has blood on one end. It can yield a lot of information about the offender and its link to our deceased.

Skip to 0 minutes and 53 secondsSo what we need to do is try and identify whose blood that is, and that's why we'll send it off to the forensic science lab. OK. This needs to be done in a sequential process, and we'll deal with the most fragile, destructive evidence first, which in this case is going to be DNA. Yes. OK, so we'll ask them to have a look at the blood, see if it can be compared against our victim's, our deceased's, DNA profile.

Skip to 1 minute and 18 secondsWe'll also ask them to look at the rest of the metal bar for any other biological fluids, for any touch DNA, do a full trace evidence recovery at that stage for extraneous fibres and hairs, and see if we can try and find a DNA profile that we could identify on our suspects, maybe by searching against the national DNA database. OK. Yeah? We also have this item here, which is a swab of blood that our examiner has recovered from the Thames path adjacent to the beach. Now, this could have been a possible egress route, which is the route most likely to have been taken by the suspect as they left the scene. I see.

Skip to 1 minute and 58 secondsSo we need that to be analysed to see if a DNA profile can be ascertained, and then compared against the national DNA database to see if, again, it can give us a name or an identification of someone that may be linked to this offence - OK. - hopefully, the suspect's. So what I need you to do now is take these items, these two items, to Dr David Ballard at King's College for further analysis and interpretation. Is that OK? Yes, I will do that. Brilliant. Thank you.

Skip to 2 minutes and 28 secondsSee you, then. Thank you. See you soon.

Back at the station

You take the evidence back to the police station with Gihan, who explains you more about the importance of each secured item and instructs you on how to proceed.

Share this video:

This video is from the free online course:

The Science Behind Forensic Science

King's College London

Get a taste of this course

Find out what this course is like by previewing some of the course steps before you join: