An Intro to Forensics: The Science of Crime

Do you enjoy crime shows and murder podcasts? If so, forensics may be for you!
In this episode of SciShow, we’re going to investigate a murder using forensics, which is the science of criminal law -- but the truth is, it's a little different than what you see on TV. Let's go!

Hosted by: Michael Aranda
----------
Dooblydoo thanks go to the following Patreon supporters -- we couldn't make SciShow without them! Shout out to Justin Ove, Justin Lentz, David Campos, Chris Peters, and Fatima Iqbal.
----------

Or help support us by becoming our patron on Patreon:
----------
Looking for SciShow elsewhere on the internet?

Sources:

[JustGrowingUp]

Oh man, this was better than an actual CSI episode...

[AH]

Lawyer: murderersaywhat
Charlie: What?
Lawyer: That's all I have to say your honor.

[SanguineUltimatum]

I did a 3 year degree in forensics and now have a Bsc(Hons) in Forensic Science. This video contained nearly a years worth of my courses information!

[WhitepawWolfGaming]

That was smooth delivery on that T-shirt ad mid-way through

[boy]

love this episode! hope there's part 2! Charlie needs to face justice!!!

[mirkwoodian]

This should be mandatory viewing for every single crime show writer that plans on involving forensic science in any way.

[VK-pkuz]

"We have a picture of the building that was robbed"
-"Wait! What's that in the window? That's a reflection of a man with sunglasses with in them a reflection of the license plate of the car the getaway car bumped into. Enhance it."
"Done."
-"Look, those scrape marks are typical <random brand>, and the paint flakes clearly show a tint of red only used in that one factory in south-east Ukraine. There's no doubt: it was the butler."

[ZRovas]

I want a SciShow Detective Drama series where they actually do it REALISTICALLY, and the selling point is they explain to you how they do it, rather than handwaving it like in TV shows. XD

[NovaPerez]

I like that you brought a better understanding to the common misconceptions of the CSI franchise. As a Forensic Science Major there's a lot that's misconstrued because of the the television series.

[jim]

Cliffhanger on a youtube video. What an age we live in xD

[monkeydunkey]

never thought I would say this on a Sci show video but please make a part two. Does Charlie get arrested? Did Bob deserve to die? Was there another suspect?

[pawelkorzeniewski]

It was nice to watch an episode that's entirely within my field, I have however 4 points/comments:

1: Although it's true that rigor mortis/livor mortis/algor mortis can be used to approximate the time after death, it is really approximate and subject to rather large variation. Good point about the ambient temperature though.

2: In Europe we use 21 STR loci for DNA analysis so the random match probability is in the tens of billions

3: the Kastle-Mayer test looks for haem as you pointed out, however as also pointed out, it utilises its oxidative properties. The problem is that any oxidising agent would work and hence some of these presumptive tests for blood would give positive results for bleach or broccoli.

4: guilty or not guilty? That's not for the forensic scientist to decide - it's the court's job

[GraeHall]

So there seems to be a bug in this video upload? The video cuts off at 9:23. I wanted to watch the 45 minutes rest of this. Because this is fascinating. And educational. And incredibly annoying in that it''s good enough that only 9 minutes feels unfairly short leaving me wanting way more :(

[Steven-wvqm]

I ain't dead. I just wanted that life insurance money.

[drink]

I wouldn't be surprised if Charlie bit that guys finger.

[JonathanWeberese]

One thing you missed was temporal enhancement. While it is indeed impossible to enhance a single image, because data is missing, you can actually interpret what is within the pixel coverage area by gathering information from other frames. It doesn't work near as well as on the shows, but it is actually part of the basis for "upsampling", when you play a standard-def DVD in a Blu-Ray player or upsampling DVD player.

If a detail, for instance, is covered by an entire pixel, it may be covered half in one pixel and half in another in the following frame. Using the data from these two frames, you can deduce more information about that detail, effectively doubling the resolution (maximum when using 2 frames. Can get greater with more frames.) It is almost entirely complex linear algebra, which video processors are specifically designed for.

Of course, the problem is that it is situational and an approximation.

[MalinIscathan]

Yes! Just yes! I'm a university student and I study forensic science. So just yes. You are right. This dear friends is basically how it works. This video made me so happy.

[vonneely]

The most unrealistic thing I've found in CSI-type shows is the notion that the police would ever spend that amount of time, effort, and expensive lab work investigating the deaths of mere average people who are neither rich nor famous.

[noodlesthest]

Charlie's guilty I tell you! GUILTY!!!

[julianalbertoarcesanchez]

You better have a Part 2 on the works. How can I ever live without knowing what really happened to Bob? (Of course, many crimes go unsolved, and families have to go on with the not-knowing; very meta if planned that way)