When Fannie Henson of Virginia found a man’s lost wallet she must have thought it was her lucky day. She took one of the man’s credit cards and ran up almost $400 in charges from a gas station and a grocery store combined. Her undoing? Ms. Henson was a smart shopper and she was sure to scan her personal discount card before paying for her groceries with a stranger’s credit card. She was soon linked to the stolen card and was arrested for credit card theft, a felony.
Shopping for a Bargain, Shopping for an arrest
February 2nd, 2010
Did you know…..
January 28th, 2010That when the Mona Lisa was stolen from the Louvre in Paris in 1911 it was fingerprint evidence that led to the capture of her thief? In 1911 the Mona Lisa was unceremoniously stolen off the Louvre walls and carried out of the museum after it closed. It took detectives two years to apprehend a suspect, Vincenzo Peruggia a Louvre employee in 1911. It was the fingerprint Peruggia left behind on the protective glass that had been shielding the Mona Lisa that finally definitely tied the thief to the crime.
For more on crimes against art come see the museum’s Temporary Crimes in the Arts exhibit, up from February 12 thru April 26, 2010. Click here for details.
3D Forensic Facial Reconstruction
January 21st, 20103D facial reconstruction is the art of reconstructing what a face might have looked like from a skull. This technique is most often used on discovered skeletal remains where the identity of the victim is unknown; it is a last resort for when all other modes of identification have failed to provide the victim’s identity. 3D facial reconstruction is not a legally recognized technique for positive identification and is not admissible in court as expert testimony.
Facial reconstruction starts with assessing the owner of the skull’s race, sex, and age. The race and sex can be determined with relatively good accuracy from the skull alone and certain age groups can be very loosely approximated from the skull as well. The process of reconstruction starts with making a mold of the unknown skull with the jaw attached and false eyes in place. Depth markers are placed on 21 different “landmark” areas of the mold of the skull to approximate the facial tissue thickness that lay on the skull. These tissue thicknesses are approximated from averages of other people of the same age, sex, and race as the skull is assumed to be. Facial muscles are placed on the mold next and then the face is built up with clay to within a millimeter of the depth markers as tissue. The nose and eye setting are very difficult to estimate due to the enormous amount of variation possible, mathematical models are used to make the approximations, the mouth is assumed to be the same width as the distance between the pupils. In facial reconstruction the eyes, nose, and mouth are mostly guess work. Characteristics such as birthmarks, wrinkles, weight, scars, and such are guesses at best and cannot actually be determined from the skull.
No single methodology has been established for 3D forensic facial reconstruction so there are a number of different methods, in the end facial reconstruction is a scientifically based artist’s rendition of what a face might have looked like. 3D facial reconstruction is considered to be inherently inaccurate and different artists, given the same skull, will always come back with different looking faces.
Mini Mystery
January 15th, 2010Detective Washington stood in the doorway looking at the dead body in the den, the body of Mr. Abrams Lincoln. Mr. Lincoln lay on the floor with blood still flowing from the obvious bullet hole in his back, the blood slowly saturating the carpet. The phone lay next to his body. Mrs. Lincoln stood in the doorway crying “I should have come home, I should have called the police” she sobbed. Mrs. Lincoln then repeated her story to the detective “I was on the phone with Abe this morning a few minutes after I arrived at work, I had forgotten to take the dog out and had called Abe to remind him to take Wolfie out.” The shaken woman continued, “We were talking when he said that he heard a crash, he said the dog probably knocked something over and then I heard a loud bang and the phone went dead. I thought Wolfie had just knocked something over and I went back to my busy day.” Mary Lincoln sputtered “I tried calling a couple of more times but the phone was always busy, but I didn’t think anything of it.” After a few deep breaths she continued “I came home and found him like this and immediately called the police. I wish I had called them when the phone went dead but I thought it was the dog and I had meetings all day, I was just so busy, I was in meetings until 6pm” finished Mary.
The detective stood and thought for a minute and asked Mary Lincoln what time she had left for work in the morning. “I left for work around 8:30am, I had gone to work early because I had so much to do, I called Abe probably around 9am” answered the widow. The detective proclaimed “Mrs. Lincoln, either you are lying to me or there were two separate incidents at this house because your husband was not shot while you were on the phone with him.”
What would cause the detective to say this?
The answer will appear in the comments section of this post on February 17, 2010
NMCP forensic crossword
January 6th, 2010
Forensic Crossword
Across:
3. A class characteristic of fingerprints
4. You can use different lights to differentiate these on paper
5. Shoe _: A type of she evidence,like in mud (also the name of one of the NMCP workshops)
8. The shell of a bullet
11. _ & Valleys : The two features that make up fingerprint patterns
12. A kind of glue used to find latent fingerprints
14. The over the counter pain reliever that was tainted with cyanide and killed seven in 1982
16. _ & Forgeries: One of the NMCP workshops
20. _ Light: A common term for UV light
21. _ Writing: A type of written evidence
22. A class characteristic of fingerprints
23. One of the words from DNA
Down:
1. “pertaining to the law”
2. The study of firearms
6. Friction _: Raised skin on the fingertips that is responsible for leaving fingerprint marks
7. Blood _ Analysis: Study of bloodstain patterns
9. Type of evidence that covicted Ted Bundy
10. One of the words from NMCP
13. Clyde’s partner in crime
15. A chemical used to detect blood
17. These types of blood cells have no nucleus and no DNA
18. One of the words from CSI
19. Type of killer who kills multiple people in a series of incidents
20. _ & DNA: The name of one of the NMCP workshops
Answers will be posted in the coments section of this post on Feb 10th, 2010
Forensic Anthropology
December 30th, 2009What do forensic anthropologists do? They study human bones to determine a biological profile and to assess potential trauma and pathology. What does that mean? It means forensic anthropologists use bones to try to understand what a given person looked like and if they suffered any trauma when they died.
So what can a forensic anthropologist tell from bones? Bones can tell age, sex, stature, bone pathology, nutrition, and sometimes repetitive activities the person had engaged in. Repetitive activity can change the morphology of a skeleton and bones; repetitive, heavy use of certain muscles can affect the size and density of the bones to which they are attached. Poor nutrition also shows up in bones. Rickets, a disease caused by vitamin D and calcium deficiencies, causes bones to become soft, fractured, and deformed.
The age of the person the bones belonged to can be determined relatively accurately using bone fusions and teeth up to the age of 21, after the age of 21 exact age is all but impossible to determine from bones, except for relative old age. Sex can be determined from close examination of the pelvis, which has gone through evolutionary differentiation between men and women, and the skull. Small shape and size differences in these bones can help determine the sex of the skeleton. Race can also be determined, somewhat. Race can be narrowed down to black, white, or Asian using the features of the skull and sometimes the shape of certain teeth. This is becoming more difficult in an age where different races interbreed freely and skull morphology of mixed races is not telling of any one race.
Forensic anthropology also concentrates on potential causes of death, although forensic anthropologists lack the legal authority to declare any official cause of death their opinions are taken into consideration by the medical examiner or coroner. The potential cause of death can sometimes be determined if there are obvious perimortem fractures to the skeleton or gunshot holes or blade cut marks in the bone.
Honest to a fault
December 24th, 2009When high school drop-out James Palmer was stopped by police for behaving suspiciously in front of a local high school Palmer tried talking his way out of trouble. This became increasingly difficult when police found an ounce of marijuana divided into several smaller bags on him, but Palmer simply explained to officers “It’s not mine. I’m selling it.” Officers were happy to hear the confession and to arrest Palmer for selling drugs in a school zone.
Sherlock Holmes and Forensics
December 17th, 2009Sherlock Holmes was a fictitious detective who is thought to have been born in the mid to late 19th century though his true birth year can be attributed to 1887 when Scottish author Sir Arthur Conan Doyle brought him to life in his first Holmes based story.
Sherlock Holmes worked as a consulting detective in London with his partner Dr. John H. Watson, who moved in with Holmes to help pay the rent. Holmes was a freelance detective as well as a forensic scientist, the first of his time. Holmes is unlike anybody we would find working in forensics today because of his disciplinary crossing reach.
Holmes worked as a detective and as such used his sharp mind to “reason backwards” or to see the conclusion of a criminal act and be able to reason backwards to find the motive and the culprit. But Holmes was much more than just a detective.
Sherlock Holmes also worked in the chemistry lab of a hospital, making him a forensic chemist. Holmes “discovered” a test to detect hemoglobin, and hence blood, he did this in Doyle’s mind 13 years before it happened in the real world. Holmes commented on the uniqueness of typewriters three years before any real life document examiners did the same. He is considered a pioneer in the use of forensic science.
Today forensic chemists do not do detective work in the field and detectives do not spend time in the laboratory examining evidence, these are two separate arms of law enforcement. Sherlock Holmes was a genius at both as best described by Doyle’s quote from Holmes’ mouth expressing both processes in one eloquent statement:
“The process… starts upon the supposition that when you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth. It may be that several explanations remain, in which case one tries test after test until one or other of them has a convincing amount of support”
For on Detective Sherlock Holmes check out the museum’s Sherlock Holmes Package and workshop on December 26th.
Did you know…
December 9th, 2009That a person can have more than one DNA profile?
There are people who are human chimeras, who are people who are made up of two different sets of cells with DNA that are only as similar as that of two non-twin siblings. This means that a person can have cheek cells that have different DNA than their skin cells. How does this happen? In a very few instances where there are two fertilized eggs in the womb (fraternal twins) the fertilized eggs fuse together, well before the embryonic stem cells of that egg have begun to differentiate into anything, and become one developing fertilized egg. These eggs carry two different sets of DNA and so the resultant embryo, which will develop into a person, will always have two sets of DNA within it, each set differentiating into some different part of the body. The forensic implications of this are that a person whose DNA is being tested from a cheek swab may not match the skin cell DNA that he/she left behind at a crime scene.
Human chimeras are thought to be very rare, blood chimeras are more common. Blood chimeras are fraternal twins who shared some portion of placenta in the womb. The sharing of placenta caused blood and blood-forming tissue to be exchanged between the twins and to embed in the bone marrow. This causes the twins to have DNA from each other in their blood, which is produced in the bone marrow. The blood of chimeric fraternal twins has two distinct sets of genes and possibly two different blood types.
Positive Identification of the Dead
December 2nd, 2009How are unknown dead bodies identified? There are actually very few ways which are considered to be positive identification methods, all other techniques are considered to be presumptive. Positive identification can be done through dental records, finger print identification, DNA analysis, and through medical implants. Most of these methods require an ante-mortem record to which post-mortem records can be compared.
Ante-mortem fingerprint records can be found in any number of fingerprint databases including the national FBI database AFIS, but if the deceased was never fingerprinted and they are not in any fingerprint database then fingerprints cannot be used to make a positive ID. Similar to fingerprints, if ante-mortem dental records cannot be obtained for the deceased then dental records cannot be used to make a positive ID. DNA analysis also requires ante-mortem records, but can use other types of records as well. For DNA testing any biological sample known to have come from the deceased can be used to get an ante-mortem profile. Biological samples such as medical samples from surgery or donor samples from the deceased’s tooth or hair brush can be used to obtain ante-mortem records, as long as only the deceased used these items. DNA identification can also be made if both parents of the deceased are alive or if the deceased had a child. The two parents’ DNA can be matched to the deceased to determine the deceased is their child. If the deceased had a child the child and the child’s other biological parent can be matched to the deceased in much the same way. In the case of dental records and DNA analysis, investigators have to have some idea or guess as to who the body might be in order to search for ante-mortem records or relatives. Using medical implants to make a positive identification does not require any ante-mortem records beyond the manufacturing data and serial number associated with the implant. Since all surgical implants require documentation of insertion in a database, any medical implant found in a dead body can be traced back to when, where, and into whom it was implanted.
Forms of identification such as visual identification or personal possessions identifications are presumptive and cannot be used as a legal determinant to assess positive identification of an unknown dead body.
