Forensic Science Blog Photo

July 28th, 2014


Helping with the identification of  an unknown individual as well as providing information about how the victim died  are two of the forensic anthropologist’s main tasks during a death investigation. As  forensic scientists we normally do not have contact with the relatives of the victims and many times our case “ends” when we submit our final report. Sometime we do not know if the victim was identified and if we do, that’s all we know. We ignore the whole story behind each case, behind each name. But there are important reasons behind naming the dead, not only those directly related to the legal process.

Who is Dayani Cristal? is the name of a film able to show all aspects of a death investigation and the humanitarian work behind it. They show real forensic and CSI work. The documentary film made by Gael Garcia Bernal and Marc Silver tells the complex story of a Honduran migrant who died in the Arizona desert in 2010 and highlights the work being done to identify him by the Pima County Police and Medical Examiner’s Office.

Kudos to the dedicated and tireless forensic and police staff of the Pima County!

Related article here.

Trailer, current screenings and much more here.



May 23rd, 2014




Arson UF


Fire investigations begin with a careful exam looking for signs of arson. Since most arsons are started with accelerants such as gasoline and those accelerants do not consume entirely during fire, some of the liquid may remain unchanged allowing its detection.

Once the samples are packaged they are sent to a laboratory for ignitable liquid residues analysis.Volatiles need to be extracted and then analyzed by gas chromatography mass spectrometry and the chromatogram will be interpreted by a fire chemist. This lab process can take a while. At this stage of the investigation, chemometrics – extraction chemically relevant information out of measured chemical data – can make a difference.  Or at least that’s what Nikolai Sinkov  and colleagues recently reported.

Press here to read more

For a great interview to the authors, press here.

February 5th, 2014





Are we as forensic scientists applying a solid scientific methodology? Are our methods valid and reliable? Do we use them appropriately in the courtroom?

Any scientific measurement has some error associated with it and forensic conclusions can be subjective and mistakes occur. Sometimes, techniques that have been properly validated are improperly conducted or inaccurately communicated in court.  These matters need to be acknowledged and discussed.

A recent article tackles these issues and I consider it to be a must-read for anyone studying forensic sciences or working in the field. The paper deals with the potential sources of error (practitioner, technological, and method error) and the misuse of this term as well as with the meaning of validity and reliability.

We need to remember that we, as forensic practitioners, provide a service to others. We must present our scientific analysis of evidence in courtroom communicating the potential sources of error in our methods and analysis.

The paper in question is:  “Error and its meaning in Forensic Science” by Angi Christensen  et al. Journal of forensic Sciences, January 2014, vol. 59, No. 1

Here’s a link to the abstract.

November 9th, 2013


Exhuming political and intellectual figures seems to be the latest forensic trend in several countries and regions. Take for example the inquiry seeking the cause of death of Yasir Arafat. The reports presented last Wednesday by the experts said Arafat did not die from old age, illness, or natural causes. They also concluded that the results “moderately support” the theory that Arafat’s death was the consequence of poisoning with polonium-210.

Latin America, in particular, is trying to extinguish the fire caused by years of political repression and terror, assassination plots, and unsolved questions through exhumations and death investigations. Recently exhumed political and intellectual figures include Simón Bolívar, Salvador Allende, Pablo Neruda, and Eduardo Frei Montalva.  

In a few days, the National Truth Commission of Brazil, formed to investigate human rights violations of Brazil’s dictatorship will exhume the remains of Brazilian ex-president Joao Goulart. The investigation team composed by experts from Brazil, Argentina, Cuba, and Uruguay will try to determine whether Goulart was poisoned in the 1970s.

João “Jango” Goulart will be given the state burial to which leaders are entitled, but which he never got.

More information here.


July 19th, 2013



Methods currently used for obtaining samples for DNA isolation are well established. In almost all protocols the specimen needs to be damaged either by crushing the entire tooth or sectioning the piece. Is there a non destructive DNA extraction method?

The answer is yes. Several authors have successfully amplified mitochondrial and nuclear DNA using non destructive methods in museum specimens (see Hofreiter 2012, Mohandesan et al. 2012, Bolnick et al. 2012 and Rohland 2004). But what about forensic cases?

A few days ago, a new method was reported. Chilean researchers Patricio Carrasco and Carolina Inostroza from the Universidad de los Andes, have obtained a provisional US patent for their novel DNA extraction system from the teeth without breaking or damaging the piece. The method, not only allows to ID the person, but also the post mortem interval and cause of death (i.e. poisoning, diseases, drugs).

They have a year to provide more scientific support to their method to obtain the complete patent.

Read more here.

June 1st, 2013

While the US Congress deliberates about changes to the immigration system, hundreds of sets of human bones remain unidentified in Arizona at the Pima County Medical Examiner’s Office. Shocking but not surprising; since the 1990s, more than 6,000 people have lost their lives crossing the U.S.-Mexico border. For a long time, identification of those remains was difficult.

One approach to solve this crisis is the use of technology. The Pima County Office and Humane Borders came up with the idea of launching a web-based system that will allow the public to identify the approximately 2000 deceased found in the desert in the Tucson area. Read more here

The web site states that they provide tools that use publicly information that allow any user to query data concerning migrant deaths, view the data using on-line apps and tables, and download the data for further use.

Visit the Arizona OpenGis Initiative for Deceased Migrants site here.

Even though more funding and cooperation is needed, this web site will help raise awareness about the dangers people face when they try to reach the US illegally crossing the border.

March 29th, 2013

A mummy is a human or animal that has been preserved, through artificial or accidental means (i.e. by exposure to chemicals, very low humidity or extreme cold, lack of air, etc.). People tend to associate the word mummy with the well-known mummies of Egypt or South America but never with contemporary preserved bodies.

From time to time, Forensic Anthropologists and other forensic scientists face the challenge of analyze and identify mummified bodies (normally through fingerprint analysis). The first stage is to rehydrate the tissues in order to regain something of its normal texture. With or without amputation of fingers, the tissues are soaked or injected with solutions in order to enhance fingerprints. The reported formulas vary from a mixture of alcohol, sodium carbonate and water; alcohol alone; fabric softener; or simply 1.2 per cent saline.

Alejandro Hernandez deals with mummies continuously. He is a forensic dentist who works in Ciudad Juarez, Mexico and has a secret formula that allowed him to rehydrate hundreds of mummies in order to identify facial features or reveal wounds related to cause of death. Read about his story here.

January 24th, 2013

We all know from our History classes that the explorer and colonizer Christopher Columbus was born in Genoa, Italy. Or at least that is the the general consensus among historians…

Recently, the forensic document examiner Jesús Delgado published a book entitled “Christopher Columbus, his origin and life examined with 21st century police techniques” (my translation of  ”Cristóbal Colón, su origen y vida investigados con técnicas policiales del siglo XXI “.

In his book , Delgado states that Columbus was from Catalonia. A careful study of files containing different types of documents revealed that the explorer lived in Barcelona, Spain and his false origin could be attributed to the Kings of Spain who were not willing to pay him and name Columbus a viceroy. Being a foreigner, he was not entitled to anything promised.

Jesús Delgado also describes the personality of  Columbus as being shy, a good father, and a dreamer.  ”This is the first book about the life of Columbus based on scientific evidence”, he states.

We will have to see what historians have to say!

For more information on Delgado’s book press here.

Read more here.

November 14th, 2012

The body of the late Palestinian leader Yasser Arafat is set to be exhumed on November 26, eight years after his death, to investigate whether he may have been poisoned. Palestinians are coordinating with Russian, Swiss, and French experts.

Mohammed Yasser Abdel Rahman Abdel Raouf Arafat al-Qudwa al-Hussein , popularly known as Yasser Arafat, the president of the Palestinian Authority and a symbol of Palestinian resistance, was a a highly controversial figure. He died in France in 2004, aged 75, a month after being flown, seriously ill, from his battered headquarters in Ramallah, and no autopsy was carried out. Allegations of foul play have long surrounded Arafat’s death, leading to persistent conspiracy theories that he had cancer, AIDS or was poisoned.

French prosecutors opened a murder investigation in August after Al-Jazeera television broadcast an investigation in which Swiss experts from the Swiss Institute of Radiation Physics in Lausanne discovered high levels of the radioactive element polonium-210 on Arafat’s clothing provided by his widow Suha.

The Polonium-210 is a highly radioactive and toxic element, present in foods in low doses. This element is very dangerous if significant doses are ingested.

Read more here and here.

October 15th, 2012

According to the IAPBA (International Association of Bloodstain Pattern Analysts, “bloodstain pattern analysis can yield valuable information concerning the events which lead to their creation when examined by a qualified analyst“.

This type of analysis involves the examination of the size, shape and distribution of bloodstains at scenes involving bloodshed in order to conduct a scientifically based reconstruction of a crime.

BPA as a forensic discipline is credited to Dr. Paul Leland Kirk. He became  involved in the famous case of Dr. Sam Sheppard. He was tried and convicted accused of murdering his wife. Dr Kirk testified at the retrial of the case, which led to Sheppard’s acquittal after serving almost a decade in prison.

Recently, scientists in Germany predict that the new insights in the field will lead to a number of criminal cases that will have to be reopened.” Ideas that were once seen as certainties in the field have been put to the test” said Dr. Silke Brodbeck, the director of the Blutspureninstitut in Germany.

It seems the 2012 IABPA Conference that will be held in Edinburgh (Nov. 12-14) will bring news around this issue.

We will keep you posted!

Read more: here

Related resources:

Scientific Working Group on Bloodstain Pattern Analysis (SWGSTAIN)