Members of the group that works on the identification of people killed in the Araguaia War in Brazil explain how their area of specialization can reveal fundamental clues that can aid in solving crimes

Forensic anthropologist seeks parameters for bone analysis
2013-06-19

Members of the group that works on the identification of people killed in the Araguaia War in Brazil explain how their area of specialization can reveal fundamental clues that can aid in solving crimes.

Forensic anthropologist seeks parameters for bone analysis

Members of the group that works on the identification of people killed in the Araguaia War in Brazil explain how their area of specialization can reveal fundamental clues that can aid in solving crimes.

2013-06-19

Members of the group that works on the identification of people killed in the Araguaia War in Brazil explain how their area of specialization can reveal fundamental clues that can aid in solving crimes

 

By Karina Toledo

Agência FAPESP – A good part of the routine of forensic scientists is dedicated to identifying people –victims of accidents, missing persons, crime suspects or simply unidentified cadavers.

Although a DNA exam is an important ally in this work, it is not the only tool available. In certain cases, bone analysis can offer even more valuable and fundamental clues to solve a mystery.

“What good is it to evaluate the DNA of a bone found in a clandestine cemetery if there is not a suspect to compare it to?” said Marco Aurélio Guimarães, responsible for the Forensic Anthropology Laboratory within the Legal Medical Center (Cemel) at Universidade de São Paulo’s Ribeirão Preto Medical School (FMRP-USP), where he addresses situations of this type daily.

“In these cases, we seek to determine the sex of the victim, the ancestry (Caucasian, African, Asian or Indigenous), age group, stature and even handedness (the with which hand they wrote). We are also seeking surgical scars, signs of trauma or anatomical alterations at birth that facilitate identification. This profile is eleased in the hopes of finding family members who can provide more information and eventually a DNA sample for comparison,” said Guimarães, one of the speakers at the 4th Brazilian Congress on Genetic Forensics, held May 7-10 in São Paulo and funded in part by FAPESP.

According to Guimarães, few districts in the country have trained inspectors to perform this type of bioanthropological analysis. Furthermore, a uniform methodology has not been well established in Brazil. Guimarães developed the protocol used by Cemel eight years ago in partnership with scientists from the University of Sheffield in the United Kingdom.

“To determine the sex, for example, we primarily use the cranium and pelvic bones. We have selected the most reliable morphological parameters found in the scientific literature, and we evaluate whether more masculine or feminine characteristics are present. In the case of stature, our baseline is long bones, and we use mathematical regression formulas to do an estimate. The state of the joints can also reveal important clues about the age range,” he said.

With this methodology, coupled with the analysis of dental records, the Cemel analysts can determine the age of one-third of the bones that come through the laboratory. According to Guimarães, this rate is comparable to that achieved by the best centers of forensic anthropology in the world.

The same technique has been employed by the scientists of the Araguaia Workgroup (GTA), which has been conducting expeditions to the north of the country in search of the bodies of communist guerillas killed during the military dictatorship (1964-1985).

‘ “If all the bones found in the region were sent for DNA analysis, the identification work would cost a fortune and offer few results. For this reason, we are screening at the excavation with the objective of determining whether the remains have a profile compatible with a guerilla fighter,” explained Guimarães.

However, to determine the ancestry and even the stature based on the established parameters, using international data could be a lengthy task in a country with as many people of mixed race as Brazil. For this reason, Guimarães is currently mentoring a doctoral student whose objective is to establish more suitable parameters for the Brazilian population.

“We are going to exhume 150 bodies that have not been claimed by family members in a Ribeirão Preto cemetery, and we will apply this protocol of analysis and compare the results obtained with those expected from the Cemel parameters. The idea is to establish more reliable national guidelines,” he explained. Raffaela Arrabaça Francisco, who is also a FAPESP fellow, conducted the study at FMRP-USP.

Guimarães stressed, however, that even the best protocol for forensic anthropology cannot resolve everything in many cases. “Many times we need to combine several methodologies of identification, such as fingerprints, analysis of the dental arch and, as a last resort, a DNA exam. They are inter-related techniques, and the recommended technique depends on each situation,” he said.

Databases of genetic profiles

Since March, when the 2012 Law 12,654 took effect, the technicians involved in identifying people have gained an important trump card. Under the law, collection of genetic material from people convicted of heinous crimes has become mandatory. The information will be stored in state databases that are connected to a national database coordinated by the National Crime Institute in Brasilia.

“The law also created the possibility of collecting the DNA of suspects of crimes as long as the judge agrees that this is essential for investigations. All these data will comprise a database that will be very useful because, although in the majority of crimes some remains are found at the locale, such as blood or semen, there is no suspect to compare them to,” explained Guilherme Jacques, a federal crime technician who works with the installation of an integrated Genetic Profiles Database.

Under the law, the Genetic Profiles Database can also be used in the identification of missing persons. “Now, it is necessary to make an announcement to the relatives of missing persons to seek out institutions and provide genetic material. These data will be stored to allow comparison with the DNA of bones and bodies found,” explained Eloisa Auler Bettencourt, crime technician at São Paulo State.

 

  Republish
 

Republish

The Agency FAPESP licenses news via Creative Commons (CC-BY-NC-ND) so that they can be republished free of charge and in a simple way by other digital or printed vehicles. Agência FAPESP must be credited as the source of the content being republished and the name of the reporter (if any) must be attributed. Using the HMTL button below allows compliance with these rules, detailed in Digital Republishing Policy FAPESP.