PostHeaderIcon Fingerprinting

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Latent fingerprints are nearly invisble to the naked eye. They’re left when someone touches an object, leaving behind sweat and oils. Detectives make the print images visible by using powder that clings to the oily ridges of the fingerprint.

 All police officers are trained to use basic fingerprinting equipment – brushes, powders, tape, and lifters.

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Basic fingerprinting kit. 

Investigators use brushes to apply print powder. The best brushes are made from the feathers of a maribou, a member of the stork family. A second type brush – camel hair – is also an excellent brush. Interestingly, camel hair brushes are not made from the hair of actual camels. Instead they’re made from the hair of small mammels, such as rabbits and squirrels. Synthetic brushes are widely used because they’re less expensive than the other types.

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Maribou feather brush

After a print has been developed, the detective uses tape that’s similar to wide packing tape to lift the print from the surface. She then presses the tape and captured fingerprint against a white card creating a permanent piece of evidence.

Another great tool – my personal favorite –  for lifting prints is a hinged fingerprint lifter. The front of the lifter is a small square of tape. The second part of the lifter is a white backing. The print is lifted with the tape which is then pressed tightly against the backing to preserve the fingerprint. Lifters come with pre-printed spaces for the date, time, officers initials, and case numbers.

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Hinged fingerprint lifter.

* All photographs courtesy of my friends at Sirchie Finger Print Laboratory

* Notice – The Graveyard Shift is pleased to announce a special guest blogger on Monday 3-3-08. Sgt. John Howsden (ret.), a thirty year veteran police officer, will be discussing body armor (Kevlar vests). Stop by and pick his brain. As usual, we’ll have some cool photographs. One is really cool.

* Fingerprinting will continue next week. Be prepared to take lots of notes.

10 Responses to “Fingerprinting”

  • pabrown says:

    All police officers are trained to take fingerprints, but in a major homicide scene, would the lead detective do so, or would a fingerprint specialist be called in to take latents?

  • Lee Lofland says:

    pabrown – It depends on the size of the department. Smaller departments may not have a specialist. I’m thinking of one particular department (there are many) with over 100 sworn police officers that doesn’t have special unit of crime scene technicians. This isn’t exactly a small department, either.

    The detectives assigned to the case does all his own printing and crime scene processing. They do have a crime scene vehicle, a van, but the detectives bring it with them to the scene. Either that or they send someone to the department to get it, if it’s needed. Mostly, they carry everything they need, other than large tools like work lights and generators, in the trunk of their car.

  • Joyce Tremel says:

    You know what our detectives’ crime scene kit is? Everything that fits is in a Sears Craftsman toolbag. When our detectives fume (Lee can explain fuming) an item for prints they use a 31 gallon Rubbermaid storage container. Yes, we’re very high tech!

  • Peg H says:

    Joyce, your department sounds like one my Hubby worked for in his first few years of police work. They had 2 full time officers and 5 part time. He was one of the part timers.

    Lee, when I was working for a retail store someone kept stealing money from my billfold. Hubby dusted some bills with a powder and using tweezers put them in my billfold and gave me a signed affidavit stating what he’d done to them to keep on hand. The bright purple stains on the culprits hands and face and her fingerprints on the money caught her later that day. When I called the local PD the officers who arrived on scene got a huge kick out of her trying to deny the theft since she’d been caught purple handed…face…shirt pocket….and money.

    Thanks again for a wonderful blog!

    Peg H :)

  • Joyce Tremel says:

    Peg, our dept. is a little bigger than that! Here’s our website if anyone wants to check it out: http://police.shaler.org/

  • Lee Lofland says:

    Joyce – I used to use a glass aquarium and a hot plate for fuming. I’m going to discuss fuming and Ninhydrin on Tuesday after Sgt. Howsden has his day.

    Peg – I have story about that purple stuff. It also comes in paste-form and works really well in situations where someone keeps pulling fire alarms over-and-over. Can’t really tell the story here, but I will say this, the stuff transfers from the fingers to other areas of the body. Since men have to touch certain things when nature calls the purlple shows up there, too. Imagine waking up in the middle of the night to “take care of pressing issues” and finding that an important body part has turned a deep purple.

    Oh, for those of you who don’t know, this stuff is invisible, but turns purple as time passes. I have some pictures of the paste and what it does to the hands (just the hands). We’ll have that as a topic one day, soon. We used it to mark money during drug deals.

    By the way, tomorrow’s Weekend Road Trip ends up in Boston.

  • Lee Lofland says:

    Oh, Joyce raised a great issue. Most departments don’t have the funds to buy all the cool gadgets and tools you see on TV. That’s why detectives have to be creative and devise other means to solve crimes. We’re a pretty crafty bunch.

  • Peg H says:

    The purple stuff reacts quickly with moisture and since the gal we caught was the person who cleaned the cages in the pet store…well lets just say de Nile is a river in Egypt and that she looked like she tangled with Barney, not Fife but the purple dinosaur.

    Peg H ;)

  • Lee Lofland says:

    You’re just too funny, Peg.

  • Elena says:

    Joyce, Shaler Township sounds like a very nice place to live. This from a woman who spent her first 30 years in Chicago, and her second 30 in Atlanta, and is now in a small city a tenth of the size of Atlanta.

    Getting used to being reasonably safe has been surprisingly difficult. I am one of few people in my neighborhood who locks my doors. It is hard to get a balance between a lifetime of very urban caution, and my current reality. So, reading that you are living in a place where they say most people won’t have need to call the police is reasurring.

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