The Ingenuity of Forensic Science: Using a Household Item to Fingerprint Mummies

I thought I should finally write something that lent to the ‘laboratory’ side of The Literary Laboratory, and since I recently read two stories about individuals who stumbled upon mummified remains in unusual and unpleasant places, I thought that would be an interesting place to begin.

As I said, I’ve read two different articles in the past month about mummies being found somewhere unexpected.


No, these mummies weren’t found by archaeologists, and they weren’t found buried in some ancient tomb.  The first mummy was found in the attic of a Pennsylvania home, the second found upon inspection of a detached garage by potential home buyers, and both discoveries answered some questions while posing many others.

The first individual was able to be identified as a young man who had lived in the house and had gone missing a few years before.  Based on the circumstances and the appearance of the body, the identification happened fairly quickly.

The second individual, however, was in much worse shape; despite some degree of mummification, initial observation failed to identify any specifics about the body.  Investigators were unable to establish cause or manner of death, let alone sex, age, or ethnicity.  At the time of writing, a forensic anthropologist had been called in to perform further examination, but no information has been released to the public.

Conditions have to be very precise for a body to mummify naturally: very cold temperatures, extreme salinity, lack of oxygen, high acidity, good ventilation, or extreme dryness.  A combination of these factors makes for even better preservation, but even then, not every body left under these conditions will become a mummy.  Furthermore, insect activity and predation frequently destroy bodies that may have otherwise been mummified had they been left alone.  And the smell of a decomposing corpse is often enough to lead to its discovery before this sort of preservation would occur.

Trust me, you wouldn’t be able to miss the smell of something dead and rottingI worked in a medical examiner’s office, and it’s a smell you notice rather quickly.

Nonetheless, there have been numerous instances of natural mummies—that it, mummies that were made by nature rather than a specific process like the kind that produced Egyptian mummies—both in the past and into modern day.  Nowadays when mummified bodies are found, there is a necessity to identify the individual, as well as to establish both a cause and manner of death.  In cases such as the ones I mentioned above, a thorough investigation would be required to determine if the death of either individual was due to foul play, but the condition of the body could potentially hinder the investigative proceedings.

Anyone who’s even vaguely familiar with one of the many crime dramas on television will be able to come up with some way that investigators can identify a body: physical attributes, dental records, unique marks such as tattoos or birthmarks, metal plates, breast implants, DNA, fingerprints—you name it, it’s probably been used as identification.

But what happens if teeth aren’t available, or if the body has no physical identifying factors?  What if the tissues are too decomposed or altered to obtain a good sample for DNA testing?

That’s where a technique known as tissue rehydration comes in.

Tissue rehydration is basically what it sounds like—rehydrating dried-out tissues.  In this case, those dried-out tissues are mummified remains, but more specifically, the fingers of the deceased individual.  By using tissue rehydration, investigators are sometimes able to restore a finger enough so that a proper fingerprint may be obtained.

Rehydrating a finger, or any tissue for that matter, is a dangerous game.  Some of the reagents used to rehydrate the tissues are harsh enough that they may actually destroy the fingerprint or other identifying markings.  Other techniques are extremely complicated, requiring long processing periods or the use of unusual and costly chemicals.  However, a number of rehydration techniques have been developed that are easy and relatively cheap to perform and still allow the finger to regain sufficient pliability and elasticity for a fingerprint may be obtained.

A recent article in the Journal of Forensic Sciences compared a few different solutions to see which would best rehydrate a finger and produce the clearest fingerprint.  This study used the fingers of a man that had been found hanging in an abandoned factory.  Decomposition made the face unrecognizable, but some of the fingers had become mummified; investigators collected five fingertips and rehydrated using different solutions.

Of the five tested solutions, the solution containing sodium carbonate managed to best restore the finger, producing a clear and distinct fingerprint, as shown here:


First of all, wow.  The sodium carbonate did fantastic work in restoring the finger to something that looked more life-like.  And look at the fingerprint they were able to produced afterwards:


I have no idea whether or not investigators were able to identify the victim, but a fingerprint like this would certainly go a long way in that process.

But the real question is why should you care?

Do a quick Google search on sodium carbonate, specifically it’s uses, and you’ll find it’s probably not what you were expecting.  Sodium carbonate is used mainly in glass manufacturing.  It’s used to balance pH levels in things such as detergents, water softeners, swimming pools, aquariums, and high school science experiments.  But it’s also found in food products, including ramen noodles, Chinese moon cakes, German pretzels, sherbet powder (which is similar to Pixy Stix and used to make treats such as sherbet lemons, AKA Dumbledore’s favorite sweet), as well as in many toothpastes—it’s part of the whitening component to make your teeth all nice and pearly.

Sodium carbonate can also be made by heating sodium bicarbonate—baking soda—for a brief time.  I’m not saying you should necessarily go home and try that, but I’m trying to make the point that sodium carbonate is a pretty common compound for us to encounter on a daily basis.

And forensic investigators were able to use it to help solve a crime.

That’s amazing, right?  But it’s not unusual; police officers, medical examiners, CSIs—they’ve used countless everyday objects to track down a suspect, stop a crime, or, as in this case, identify an unknown body.  Everyone thinks that solving a crime takes all sorts of fancy techniques and equipment, and sometimes it does.  But sometimes it just takes a little ingenuity and some good old-fashioned experimentation to crack a case.  In this instance, it took some transformed baking soda to de-mummify a man’s finger and likely help towards his identification, meaning that his loved ones could finally have answers as to the man’s fate.  It’s bizarre, but it’s totally brilliant.

Sherlock Holmes would be proud.

References & Additional Reading:

Chen, C.C., Yang, C.K., Chen, C.Y., Lee, H.C, Wang, S.M.  (2017), Comparison of Rehydration Techniques for Fingerprinting the Deceased After Mummification.  J Forensic Sci, 62: 205-208.

Harding, B. E. and Wolf, B. C. (2015), The Phenomenon of the Urban Mummy. J Forensic Sci, 60: 1654–1657.

Loreille, O. M., Parr, R. L., McGregor, K. A., Fitzpatrick, C. M., Lyon, C., Yang, D. Y., Speller, C. F., Grimm, M. R., Grimm, M. J., Irwin, J. A., Robinson, E. M. (2010), Integrated DNA and Fingerprint Analyses in the Identification of 60-Year-Old Mummified Human Remains Discovered in an Alaskan Glacier. J of Forensic Sci, 55: 813–818.

Schmidt CW, Nawrocki SP, Williamson MA, Marlin DC. (2000), Obtaining fingerprints from mummified fingers: a method for tissue rehydration adapted from the archeological literature. J Forensic Sci, 45:874-875.


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