How Accurate is CSI
This edition of brain rant was going to discuss the accuracy of the above franchise television series but researching it was a quagmire of scientific jargon and would not really be all that relevant to what is essentially TV drama. So I will focus on only a couple of items of interest for this article.
1. The speed in which DNA can be analyzed and interpreted in the real forensic world and compare it to the television program.
2. The clothing that should be worn at a crime scene, and what the actors wear.
3. Compare the speed at which ballistic evidence can be interpreted from actual world to the dramatic world.
4. Do the real American CSI’s actually carry side-arms?
I choose these four points because they feature heavily in all three versions of the show. I do understand that the shows are heavily constrained to time limitations and do have to use a little dramatic licence in telling the story in a succinct manner for the viewer. And that the science used is an abridged version of what happens in actuality. But they still have to make it accurate because science is in fact the lead character in the show; the actors are the ones who have to bring it to life.
Point 1 DNA.
As we all know DNA can be taken from blood, hair, saliva, and other bodily fluids including vomit and semen. The larger the sample found the quicker a DNA profile can be made. With smaller samples it can take up to a month to produce a DNA profile. It is here that the show uses the most dramatic licence because their profiling is in done in minutes but the way in which they produce a DNA profile is accurate below describes how it is done:-
1. Separate white and red blood cells with a centrifuge.
2. Extract DNA nuclei from the white blood cells. This is done by bathing the cells in hot water, then adding salt, and putting the mixture back into the centrifuge
3. Cut DNA strand into fragments using a restriction enzyme.
4. Place fragments into one end of a bed of agarose gel with electrodes in it. Agarose gel is made from agar-agar, a type of seaweed that turns into gelatin when dissolved in boiling water.
5. Use an electric current to sort the DNA segments by length. This process is called agarose gel electrophoresis. Electrophoresis refers to the process of moving the negatively-charged molecules through the gel with electricity. Shorter segments move farther away from their original location, while longer ones stay closer. The segments align in parallel rows.
6. Use a sheet of nitrocellulose or nylon to blot the DNA. The sheet is stained so the different lengths of DNA bands are visible to the naked eye. By treating the sheet with radiation, an autoradiograph is created. This is an image on x-ray film left by the decay pattern of the radiation. The autoradiograph, with its distinctive dark-colored parallel bands, is the DNA profile.
Point 2 Clothing worn by CSI’s
The real scene of crimes investigators actually wear white polyester or cotton all in one coverall. They also wear a hairnet and that is covered with a cap. Over their shoes they also have covers made of the same material as the coveralls. This is done to avoid contaminating a crime scene. The kits they carry for detection used in the series are also wholly accurate. So the CSI’s in the series are not dressed correctly but the audience does need to see the characters, otherwise the show would resemble that scene from the Woody Allen movie Everything You Wanted to know about sex but were too afraid to ask, you all know which scene I am referring to.
Point 3 Ballistic Evidence
Ballistic comparison is a time quick thing to do. Guns have rifling in the barrels which cause a bullet to spin as it leaves the barrel; this is done to increase accuracy and range of the bullet. These machining marks that are in the barrel are then transferred to the projectile as it leaves the firearm. This is called striation. Different gun manufacturers have different rifling characteristics which allow experts to narrow down the scope of investigation, and can tell which manufacturers use those characteristics all they need is weapon to compare it to. When they have a suspect weapon it is test fired into a tank of water or into a canister filled with plastic balls. This is done to avoid damaging the bullets striation. Then the test bullet is compared to the bullet recovered from a body or crime scene under a microscope and the result is instance, either a yes or no answer. The show is correct and accurate in it’s depiction of ballistic evidence.
Point 4 Are CSI’s armed?
The answer to this particular question depends on where they are based. If they are sworn in law enforcement officials then yes they are, which is true for the Miami and New York shows, their real life CSI’s do pack heat. As for Las Vegas I couldn’t find out the answer to that question. Some police departments use outside contractors for crime scene investigation, they are not armed but do carry pepper spray. In these cases the scenes are guarded by law enforcement officials.
This edition of brain rant was going to discuss the accuracy of the above franchise television series but researching it was a quagmire of scientific jargon and would not really be all that relevant to what is essentially TV drama. So I will focus on only a couple of items of interest for this article.
1. The speed in which DNA can be analyzed and interpreted in the real forensic world and compare it to the television program.
2. The clothing that should be worn at a crime scene, and what the actors wear.
3. Compare the speed at which ballistic evidence can be interpreted from actual world to the dramatic world.
4. Do the real American CSI’s actually carry side-arms?
I choose these four points because they feature heavily in all three versions of the show. I do understand that the shows are heavily constrained to time limitations and do have to use a little dramatic licence in telling the story in a succinct manner for the viewer. And that the science used is an abridged version of what happens in actuality. But they still have to make it accurate because science is in fact the lead character in the show; the actors are the ones who have to bring it to life.
Point 1 DNA.
As we all know DNA can be taken from blood, hair, saliva, and other bodily fluids including vomit and semen. The larger the sample found the quicker a DNA profile can be made. With smaller samples it can take up to a month to produce a DNA profile. It is here that the show uses the most dramatic licence because their profiling is in done in minutes but the way in which they produce a DNA profile is accurate below describes how it is done:-
1. Separate white and red blood cells with a centrifuge.
2. Extract DNA nuclei from the white blood cells. This is done by bathing the cells in hot water, then adding salt, and putting the mixture back into the centrifuge
3. Cut DNA strand into fragments using a restriction enzyme.
4. Place fragments into one end of a bed of agarose gel with electrodes in it. Agarose gel is made from agar-agar, a type of seaweed that turns into gelatin when dissolved in boiling water.
5. Use an electric current to sort the DNA segments by length. This process is called agarose gel electrophoresis. Electrophoresis refers to the process of moving the negatively-charged molecules through the gel with electricity. Shorter segments move farther away from their original location, while longer ones stay closer. The segments align in parallel rows.
6. Use a sheet of nitrocellulose or nylon to blot the DNA. The sheet is stained so the different lengths of DNA bands are visible to the naked eye. By treating the sheet with radiation, an autoradiograph is created. This is an image on x-ray film left by the decay pattern of the radiation. The autoradiograph, with its distinctive dark-colored parallel bands, is the DNA profile.
Point 2 Clothing worn by CSI’s
The real scene of crimes investigators actually wear white polyester or cotton all in one coverall. They also wear a hairnet and that is covered with a cap. Over their shoes they also have covers made of the same material as the coveralls. This is done to avoid contaminating a crime scene. The kits they carry for detection used in the series are also wholly accurate. So the CSI’s in the series are not dressed correctly but the audience does need to see the characters, otherwise the show would resemble that scene from the Woody Allen movie Everything You Wanted to know about sex but were too afraid to ask, you all know which scene I am referring to.
Point 3 Ballistic Evidence
Ballistic comparison is a time quick thing to do. Guns have rifling in the barrels which cause a bullet to spin as it leaves the barrel; this is done to increase accuracy and range of the bullet. These machining marks that are in the barrel are then transferred to the projectile as it leaves the firearm. This is called striation. Different gun manufacturers have different rifling characteristics which allow experts to narrow down the scope of investigation, and can tell which manufacturers use those characteristics all they need is weapon to compare it to. When they have a suspect weapon it is test fired into a tank of water or into a canister filled with plastic balls. This is done to avoid damaging the bullets striation. Then the test bullet is compared to the bullet recovered from a body or crime scene under a microscope and the result is instance, either a yes or no answer. The show is correct and accurate in it’s depiction of ballistic evidence.
Point 4 Are CSI’s armed?
The answer to this particular question depends on where they are based. If they are sworn in law enforcement officials then yes they are, which is true for the Miami and New York shows, their real life CSI’s do pack heat. As for Las Vegas I couldn’t find out the answer to that question. Some police departments use outside contractors for crime scene investigation, they are not armed but do carry pepper spray. In these cases the scenes are guarded by law enforcement officials.
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