Many of José Almirall’s chemistry students aren’t old enough to remember a world without primetime crime dramas like “CSI” and “Dexter,” featuring forensic scientists who close the case before the commercial break.
These TV programs – though often inaccurate and sensationalized, the AAAS Member and newly elected 2020 AAAS Fellow says – captivate generations of prospective crime-fighters who might not have otherwise considered a career in STEM.
“I think [these shows are] a good thing,” says Almirall, a professor at Florida International University. “It makes young people aware that science can be cool and important in solving societal problems.”
Almirall, with more than 30 years of experience in forensic science, reminisces about the start of his own career. As a chemistry graduate student at the University of Miami, he answered an ad from the Miami-Dade Police Department seeking a forensic chemist.
In 1986, drugs and drug-related crimes gripped the city. Almirall spent his first six years with the department as a drug chemist, identifying controlled substances using chemical processes.
“What is that white powder that was seized from a suspect? Presumptively, it may be a drug, but that analysis has to be independently verified,” Almirall says.
He went on to spend six years as a trace evidence examiner using analytical tools to piece together crime scenes from debris barely visible to the naked eye. The classic hit-and-run – rife with tiny shards of glass and plastic – was one of his most common cases.
“The suspect would strike somebody and leave the scene. They would just leave the car and go home,” he says. “Even though you can identify the owner of the car, you still have to place that person in that car at the time of the accident.”
Tiny glass fragments, Almirall says, might stick to the suspect’s clothing. This glass – depending upon where and when it was manufactured – has a characteristic chemical signature that includes impurities at very low concentrations that may be compared to a windshield or broken-in window from a known source. The trace elemental signature within the glass, measurable with sensitive instruments, provides chemical information that can be used for comparison between a fragment recovered from a suspect or a victim to a known source, Almirall says.
“The more unusual the glass is,” he adds, “the more valuable the evidence is.”
After his days as a crime-solving scientist, Almirall joined the full-time faculty at FIU in 1998 and continued to perfect methods of trace evidence analysis including glass characterization.
Almirall’s technique relies on Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS), a tool frequently used in geochemistry and analytical chemistry to measure the composition of solid materials. First, a laser beam is focused on the sample, removing a small layer of glass. This step is similar to laser eye surgery, which lifts tissue in the eye to improve your vision, Almirall says. Next, the ejected particles from the glass sample are introduced into plasma at temperatures approaching 10,000 Kelvin – nearly twice as hot as the surface of the sun. The plasma provides the energy to excite and ionize atoms which are detected and quantified by a mass spectrometer, an instrument that provides information about the sample’s elemental composition.
With this technology, “We can tell you what elements are present and their concentrations,” Almirall says. “That’s how we can characterize the trace element content of the glass.”
In perfecting these processes, Almirall is most interested in providing standardized methods of analyses that can be replicated by scientists worldwide. “If you have different chemists analyzing the same evidence, they need to come to the same conclusion,” Almirall says.
His team has co-authored five standards in forensic science, including two on the analysis and comparison of glass composition, for ASTM International, an organization that develops and publishes technical standards for many industries.
Much of Almirall’s recent work involves bridging the gap between forensic scientists in the field and in academia. He previously served as director of the International Forensic Research Institute at FIU, founded in 1997 to educate forensic scientists and conduct research. Currently, he leads the Center for Advanced Research in Forensic Science, a National Science Foundation-funded multi-university cooperative of which FIU is a member.
Almirall’s specialties go beyond glass analysis, and in 2016, he chaired a AAAS working group to identify critical issues in the field of fire investigation.
“Oftentimes, fire scene investigators are not trained scientists,” he says. “They may be firefighters that receive additional training in investigating fires but they don’t always have a scientific background. One of the recommendations in the AAAS report is related to the importance of training in, and application of the scientific method.”
Whether it be at a scene of a fire or a drug-related crime, forensic science often requires techniques that are only available in a laboratory setting. Almirall – with six patents aimed at miniaturizing analytical equipment – hopes to make analysis more portable and accessible, bringing the tools of the trade closer to the crime scene. For example, some fleeting evidence such as gunshot residue can benefit from collection and analysis in the field to minimize loss or contamination in transit from the crime scene to the lab.
“There are particles that come out of the gun when it’s fired, and they stick to the body,” he says. “The sooner you detect those particles, the better. They don’t persist for a long time.”
Faster identification of evidence speeds up the wheels of justice – albeit not as fast as you see on TV.
“The best method is to do analysis in the field,” he says. “If you could do this reliably, that saves a lot of time and effort and could also make the quality of information much better.”