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Crime Story Help: Frozen Blood Dagger?

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  1. Jul 6, 2015 #1
    Hello!

    I guess this makes for a rather ...unusual first post and I'm not sure whether this is the right thread, but I'm writing a crime story that I would like to be scientifically accurate (I swear I will only use this information for fiction, haha) and was contemplating the murder weapon, when I started thinking about making the murder weapon out of the victim's blood. Would this actually work? What would be the consequences? Ideally, the weapon would disappear after some time, but would forensics be able to tell the dagger blood and the body blood apart or would it seem like there was no murder weapon at all?
    Also, how long would it take for it to melt if there was, say, an open fireplace next to the body? And would the frozen blood inside the body (once the dagger was in there) melt faster than the blood outside?

    Well, I hope this doesn't get me on any blacklists, but sadly, I just don't have any doctor friends whom I could pester with these kinds of questions, so I turn to you, doctors of the internet! Any help is gladly appreciated :)
     
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  3. Jul 6, 2015 #2

    Drakkith

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    I'm not medical expert, but I would think the blood cells would exhibit some kind of damage from being frozen. I searched google and found an article on red blood cell hemolysis. See the 2nd page here: http://www.pall.com/pdfs/Medical/RBCHemolysis.pdf

    Your question isn't easy to answer. It depends on how close to the fire the weapon and body are and the physical dimensions of the weapon. To throw out a random guess, I'd say maybe 5-10 minutes?
     
  4. Jul 7, 2015 #3

    HallsofIvy

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    Can anyone remember the name and author of the story in which a woman killed a her husband with a frozen leg of lamb, then roasted it and fed it to the detective?
     
  5. Jul 7, 2015 #4

    Doc Al

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    Lamb to the Slaughter
     
  6. Jul 7, 2015 #5

    Drakkith

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    ?:)
     
  7. Jul 7, 2015 #6

    Evo

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  8. Jul 8, 2015 #7

    Doc Al

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    Yes, a classic. Roald Dahl was great.
     
  9. Jul 8, 2015 #8

    HallsofIvy

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    Thanks. I remember now I first saw it on Hitchcock, later read the story in a short story collection.
     
  10. Jul 15, 2015 #9

    DHF

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    I would be concerned that the dagger wouldn't have the structural integrity to stab someone to death, I don't know if frozen blood is tougher then water but water ice wouldn't make a very good knife or sword. maybe a bludgeoning weapon, that would work but the question then is how does your murder acquire that much of the victim's blood in order to craft the weapon. Unless the victim regularly donated and the murder was a medical professional who intercepted the blood donations. This would have to be done over an extended period as they don't let you donate more then a pint at a time.

    Of course this is overly complicated as the murderer could simply fashion a club out of water ice and beat the life out of their intended victim then toss the ice club into the fire. poof. no murder weapon. However that would rob all the spice out of your plot and make it rather mundane.
     
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