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989 Questions

Last Answer on July 21, 2022

Will a dry blood stain on rocks, say the interior of a cave, appear red after at least a year or would the stain be darker or change because of the conditions within the cave?

Asked by MK over 9 years ago

It will turn a dark red brown once it's completely dry, and will stay that color so far as I know if conditions stay consistent. If it changes further it would probably just fade a bit.

839 Votes

Thanks so much for answering that! Yeh, the criminals used other peoples hair. Would it be possible to blend the different types of hair with water so you could spray it on the scene of a crime? would it be the same result as leaving the hair intact?

Asked by Lisa fan about 9 years ago

Wouldn't that get the whole crime scene wet? And wouldn't a layer of hair indicate that the hair was a diversion, since obviously no one would normally shed that much hair while committing a crime. It scattering hair wouldn't affect fingerprints or touch DNA, which crime scene techs would be looking for more than hair anyway. Most labs don't even analyze hair any more. Also, I should clarify, hair cells don't have nuclear DNA. DNA in hair usually comes from the skin cells that hold the hair in your scalp and cling to the root. So if you're using cut hair there would not be any nuclear DNA to obtain. Mitochondrial DNA is a different type of DNA present in your cells' mitochondria. It will be the same throughout your body but is passed down unchanged from mother to child so it will be identical with your mother, your mother's siblings (assuming the same grandmother), your siblings from the same mother, your first cousins from your maternal aunts, etc. But very very few labs test mitochondrial DNA so it's unlikely it would be tested from your crime scene unless it was extremely high-profile and they had no other evidence to use. And then they'd have to have a suspect to compare it to or it would be useless. (CODIS, the national DNA database, is nuclear DNA.)

839 Votes

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Many cold cases have unidentified victims but how come they are unidentified when you have fingerprints and hair, etc, i don't understand why cant they know who they are when they have that.

Asked by lily over 8 years ago

Because not everyone's fingerprints are in a database. You only have fingerprints taken when you are arrested or apply for a job or some other license for which it is required. Not all of those necessarily end up in a database accessible to the agency that has the unidentified person. And DNA such as hair only helps when you have a profile to compare it to--if the unidentified person is a convicted felon so their DNA might have been entered when they went to prison, or if there are family members available to give a sample (in which case you would have to already have an idea of who the person might be). It's not really like TV. We don't have databases of every single person and every single substance known to man.

837 Votes

How long would it take for a deceased body to drop below 32 degrees centigrade if they were in good health previously and the ambient temp was 17 degrees centigrade. Would the body be cold and blue to touch inside 2 hours?

Asked by Iain about 9 years ago

I'm sorry but I have no idea. That's a question for a pathologist. Sorry I couldn't help!

837 Votes

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Do firearms have a unique spray pattern when fired? Something similar to a fingerprint?

Asked by Marco over 8 years ago

No. You might be able to estimate muzzle to target distance from a spray pattern, but not firearm type or brand.

837 Votes

Would there be DNA left if someone used a forge and turned a murder weapon (say a knife) into something else, or maybe just folded the steel multiple times?

Asked by RDSBandit about 9 years ago

I'm fairly sure that the high temperatures used in melting metal would destroy any DNA.

837 Votes

Hello, my name is Maria and I'm currently a High School senior. For my college and career project I need to interview someone in my field of interest which is forensics. Is it possible I could interview you through FaceTime or something? Thank you:)

Asked by mariataipe1523 about 9 years ago

Sure, send me your email address. If you don't want to post it here you can email me through my website: www.lisa-black@live.com.

835 Votes

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Forensic Scientist

Ask me anything!

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Will a dry blood stain on rocks, say the interior of a cave, appear red after at least a year or would the stain be darker or change because of the conditions within the cave?

Thanks so much for answering that! Yeh, the criminals used other peoples hair. Would it be possible to blend the different types of hair with water so you could spray it on the scene of a crime? would it be the same result as leaving the hair intact?

So you wanna be a Forensic Scientist?

Many cold cases have unidentified victims but how come they are unidentified when you have fingerprints and hair, etc, i don't understand why cant they know who they are when they have that.

How long would it take for a deceased body to drop below 32 degrees centigrade if they were in good health previously and the ambient temp was 17 degrees centigrade. Would the body be cold and blue to touch inside 2 hours?

Also on Jobstr...

Do firearms have a unique spray pattern when fired? Something similar to a fingerprint?

Would there be DNA left if someone used a forge and turned a murder weapon (say a knife) into something else, or maybe just folded the steel multiple times?

Hello, my name is Maria and I'm currently a High School senior. For my college and career project I need to interview someone in my field of interest which is forensics. Is it possible I could interview you through FaceTime or something? Thank you:)

Forensic Scientist

Ask me anything!

What do YOU do?

Will a dry blood stain on rocks, say the interior of a cave, appear red after at least a year or would the stain be darker or change because of the conditions within the cave?

Thanks so much for answering that! Yeh, the criminals used other peoples hair. Would it be possible to blend the different types of hair with water so you could spray it on the scene of a crime? would it be the same result as leaving the hair intact?

So you wanna be a Forensic Scientist?

Many cold cases have unidentified victims but how come they are unidentified when you have fingerprints and hair, etc, i don't understand why cant they know who they are when they have that.

How long would it take for a deceased body to drop below 32 degrees centigrade if they were in good health previously and the ambient temp was 17 degrees centigrade. Would the body be cold and blue to touch inside 2 hours?

Also on Jobstr...

Do firearms have a unique spray pattern when fired? Something similar to a fingerprint?

Would there be DNA left if someone used a forge and turned a murder weapon (say a knife) into something else, or maybe just folded the steel multiple times?

Hello, my name is Maria and I'm currently a High School senior. For my college and career project I need to interview someone in my field of interest which is forensics. Is it possible I could interview you through FaceTime or something? Thank you:)

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