Forensics Questions

11krage sounds like you've got killer intentions! :lol: Doohickey is a word usually used for things you can't remember the name of. But it is also used to refer to specific gadgets that are used as weapons.
As for your second question, I don't know much about weapons but I would suggest a slingshot :lol:
 
11krage said:
3. If a prefired bullet is slightly misshapen through previous impact will this affect its trajectory or impact affect?
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Don't know about the rest of the questions but the answer to this question is definately yes. The shape of a bullet is made completely round to have as less friction as possible with the air surrounding it. Any blockage or bulk on the bullet would result in spinning, and thus changing the directory.
 
Thank you for the answers. I would guess from further review of csi since then, since silencer barrels add extra striation markings, this would be the same effect if shooting a prefired bullet. But since the one in hodges episode left no extra striations, perhaps the length of the barrel is a deciding factor, or the method of proposion. Translating this into greater distance may require a longer barrel/ greater proposion than hodge's weapon, which may effect the striation. If anyone manages to watch that episode and they name the prosion used or mechanism, I would be grateful if you told me it so I could use it to guide my research. I'm having a little trouble getting ahold of that particular episode.

Thank you hush for your answer, I think I understand that aspect better now.

Don't worry Roka4csi, no homicidal intentions here. Just plotting out various twists I may or may not add to a storyline I'm writing.
 
Well, according to the episode review (8x08: You kill me) on Wikipedia, it was "a homemade zip-gun hidden in a box, activated by a pager"

homemade guns' barrels haven't got striations, because they're made from tubes used normally for other things (the striations are made specially for every fire weapon, and it's different between brands and models) ... as wikipedia says:

"The essential part of any improvised firearm is the barrel and chamber. For small, low pressure cartridges, like the common .22 caliber (5.5 mm) rimfire cartridges, even very thin walled tubing will suffice. Author Harlan Ellison describes the zip guns used by gangs in 1950s New York City as being made from tubing used in coffee percolators or automobile radio antennas, strapped to a block of wood to serve as a handle. A rubber band provides the power for the firing pin, which is pulled back and released to fire. The use of such weak tubing results in a firearm that can be more dangerous to the shooter than the target; the poorly fitting smoothbore barrel provides little accuracy, and is liable to burst upon firing, injuring the shooter.[1] "


so the length of the barrel (in this case) will only affect the distance, not the striation... and the method of proposion hasn't got anything to do.

(hope you understand, It's kinda messy :lol:)
 
Mrs. Sanders said:
Well, according to the episode review (8x08: You kill me) on Wikipedia, it was "a homemade zip-gun hidden in a box, activated by a pager"

homemade guns' barrels haven't got striations, because they're made from tubes used normally for other things (the striations are made specially for every fire weapon, and it's different between brands and models) ... as wikipedia says:

"The essential part of any improvised firearm is the barrel and chamber. For small, low pressure cartridges, like the common .22 caliber (5.5 mm) rimfire cartridges, even very thin walled tubing will suffice. Author Harlan Ellison describes the zip guns used by gangs in 1950s New York City as being made from tubing used in coffee percolators or automobile radio antennas, strapped to a block of wood to serve as a handle. A rubber band provides the power for the firing pin, which is pulled back and released to fire. The use of such weak tubing results in a firearm that can be more dangerous to the shooter than the target; the poorly fitting smoothbore barrel provides little accuracy, and is liable to burst upon firing, injuring the shooter.[1] "


so the length of the barrel (in this case) will only affect the distance, not the striation... and the method of proposion hasn't got anything to do.

(hope you understand, It's kinda messy :lol:)
Click to expand...

Brilliant, I think that answers all my questions and the whole deal makes so much more sense now, so thank you. :D
 
Hey I'm just watching CSI:NY and noticed that all the female CSIs have very long hair. Do real CSIs have to wear hairnets or something? Because I know my hair falls out a lot and that would probably contaminate evidence all the time.
 
I don't know about the policies in real life, but even men's hair fall out (speaking from experience). The only problem with a TV show is that the ratings would not be so good if the attractive casts were hidden behind goggles, face masks, and hairnets.

There was a TV show back in 1989 called "Unsub" starring David Soul and Kent McCord. At each crime scene, the investigators wore white suits that covered their whole body, except for the clear plastic face mask. It only lasted eight episodes.

As has been discussed before in several threads around this board, the producers take a lot of short cuts to fit the story into the 60 minutes (45 without commercials). DNA test results come back in minutes. Fingerprint searches pop right up. Maybe someone in the business can tell what really occurs at the scene. Hope this helps.
 
I attended a talk with a real forensics person from the Hillsboro Police Department, and Dynamo is correct - they wear basically bunny suits and booties to not contaminate the scene. Not terribly fun for TV viewers! DNA results can sometimes take months or even years to come back, and they don't test every little thing because it is an expensive process, so unlike the show where they test every cigarette, every glass, that would not actually be done. Fingerprints are also manually evaluated first before being entered into the computer. The analyst selects the key points on the print he or she thinks are the identifying features of the print, and again, results are not instantaneous. You may have a 10-card on someone and a partial index finger print, but you don't know what finger you have, so the computer is running all 10 to compare, times however many people are in the database. TV shows you the art, but it really is more hard core science.
 
I've seen a special on our CSI techs here in Orange County, Fl and they do wear booties and gloves and most of the female collectors who had long hair had their hair back in ponytails. They all wear cargo style pants and polo shirts that say Crime Scene Investigators on the back of them. I think in the labs they are more careful about how they treat the samples though.
 
I have a question. On certain crime shows, when entering the room the light is switched on, while on others they use flashlights. Is turn on the light considered altering the crime scene?
 
That's a really good question. I have wondered about that too. Maybe someone else knows the answer.
 
Just guessing here.

First, there might be fingerprints on the switch. Even though many switches are small, they might get a partial print.

Second, when they use their ALS (alternate light source / flashlight), they might not want too much background light so they can find certain things like blood, bodily fluids, hair, cloth fibers, etc.
 
Those were basically my thoughts too on why they might do it that way. Plus maybe they want the viewpoint of how the killer might have seen it, if the lights were off.
 
you're basically right :)

according to my teachers, the conditions of a crime scene (climate, illumination, etc) should not be altered... at least not without taking notes/pictures/videos first...

if the first personnel who arrives at the scene (police officers) have to alter something (for example, break the door to enter the scene) they must communicate it to the crime scene investigators.

hope it adds something
 
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