See how carbon dating and accelerator mass spectrometry helped law enforcement unravel a 30-year old case, revealing the story of an unknown person’s life and death. In this blog, we look at the intriguing process of forensic facial comparison and how its use by the authorities has changed over time in line with advancements in science.
Revealing the Unseen
After local law enforcement exhausted leads in Opening the Cold-Case Vault their investigation, they approached the experts at Lawrence Livermore National Laboratory’s Center for Accelerator Mass Spectrometry (CAMS) to use that facility’s systems to help solve a couple of cold cases.
The CAMS team was able to use state-of-the-art carbon dating technology on the teeth and hair of an unidentified man, ‘John Doe’ seen above (left), to pinpoint specific information about the life and death of the individual in question. The researchers estimated the year of birth and death of the man by measuring carbon-14 content in these samples, leaving behind key evidence for further investigation.
The novel forensic approach, known as bomb pulse dating, employs the distinct levels of carbon-14 and above-ground nuclear tests that occurred during the mid-20th century. Through this comparison of carbon-14 in the remains of the unknown man, to atmospheric records from the periods before and after his death, researchers can now deploy a date range both when this person was born, and died.
Unraveling the Mystery
An example of this remarkable technique is the twenty-four-year search for the identity of a Cuban male, Temistocle Fernandez Casas, whose remains were eventually identified in 2016.
The carbon dating analysis initially indicated the man was born in 1958 and died in his mid to late 30s between 1994-1997. It was a nice confirmation but still left the person anonymous — until recently.
Detectives used a familial genetic genealogy, which provided them with the genome of Mr. Fernandez’s first cousin, enabling investigators to conclude: “Case closed; we found John Doe.” This groundbreaking new discovery, occurring long after the original case took place (almost 20 years), underlines that even cold case thaws through advancements in forensic science.
Since the atmospheric bomb pulse will serve as a reference point, “having access to an accelerator mass spectrometry instrument with the precision you can get at CAMS is critical because it provides such tight bounds on how well — down to one year — we can say when someone was born or when they died,” said LLNL scientist Bruce Buchholz. Developing and delivering intelligence at this level of granularity is imperative for law enforcement to have the certainty required to act decisively, while also moving investigations forward.
Conclusion
The cold case of Temistocle Fernandez Casas is one of the best ways to show how modern techniques like carbon dating and accelerator mass spectrometry are able to provide with new answers from the past, solve some mysteries about who was laid to rest (and written on a tombstone) and help families and whole communities getting closure. As the years roll on and the ‘bomb pulse’ effect fades in nature, these high-tech tools will only get better, helping us meet some of our most challenging scientific and forensic questions — getting closer to grasping the carbon cycle all around us, and solving whatever enigmatic case may come along.
