Alternative Light Sources and forensic creativity identify suspects in armed robberies

The Mile High city of Denver, Colorado faced a notable criminal investigation. A series of four armed robberies unfolded, leading law enforcement professionals on a determined pursuit of justice. The incidents were characterized by their audacity and escalating violence, occurring within the span of eight hours on September 6, 2021.

While three of these robberies transpired within the city limits of Denver, the fourth took place in Arvada, a neighboring jurisdiction.

The perpetrators' modus operandi was marked by a calculated approach to avoid detection. The criminals, captured on surveillance footage, took precautions by wearing gloves during their actions, thwarting fingerprint collection at the crime scenes. Despite this challenge, a significant link emerged as a constant—each crime was facilitated through the use of a stolen Toyota Tacoma.

The events took a decisive turn two days following the spree when the stolen vehicle was discovered by Denver law enforcement officers within their city's jurisdiction. A vehicle occupied by multiple suspects was soon the focal point of a tense pursuit. During the chase, the suspects, in an act of desperation, fired multiple shots at the pursuing officers. The chase reached its dramatic conclusion when the vehicle crashed in Thornton, Colorado, and the perpetrators managed to evade apprehension, disappearing into the night.

Despite the absence of suspects at the crash scene, the stolen Toyota Tacoma emerged as a pivotal piece of evidence connecting the crimes. The following day, September 9, 2021, a meticulous and skilled detective, Todd Cole, spearheaded the careful analysis of the abandoned vehicle. With the assistance of their specialized Crime Scene Unit, latent prints were expertly collected from the vehicle. Additionally, the vehicle's interior yielded valuable items earmarked for latent print chemical processing, in response to a request by the detective.

In a remarkable turn, the path to identifying the culprits took an unconventional route—a discarded open cigarette pack found within the vehicle. This seemingly insignificant item held a latent print, offering a name as well as two latent fingerprint lifts from the vehicle itself. On September 10, 2021, these revelations, in conjunction with photos recovered from a cell phone from the scene, coalesced to form a comprehensive profile of a prime suspect—Miguel Serena-Serna, 19.

The detective's pursuit of justice intensified on September 27, 2021, with the issuance of a warrant for Serena-Serna's arrest. The potency of cell phone photos, combined with the cigarette pack's print, fortified the case against him. The detective's diligence was rewarded on November 21, 2021, when Serna-Serna was taken into custody. Ultimately, Serena-Serna pleaded guilty to charges of aggravated robbery on April 22, 2022. His sentence, three years in the youth offender system with a suspended Colorado Department of Corrections sentence of 12 years, underscored Colorado's unique approach to young adults aged 18 to 21.

While justice prevailed in this case, it revealed the complexities of the legal landscape. Serena-Serena's co-conspirators, who were juveniles, accepted plea deals within the juvenile system. The delicate balance between rehabilitation and retribution was evident, particularly as Miguel's sentence took his age and potential for transformation into account.

Throughout the investigation, Detective Todd Cole's efforts stood out, reflecting the dedication of law enforcement professionals. His work, supported by team members like the dedicated Crime Scene Unit, demonstrated the intricate weave of evidence and analysis in the pursuit of the truth. The detective's statement underscored the sense of responsibility toward victims and the larger community, even when outcomes differed from expectations.

Cole said, “Whatever system you had to assist in obtaining and identifying the fingerprints was a great asset to this pattern of robberies.”

In the realm of forensic investigation, Amy Williams emerges as a pivotal figure—a seasoned forensic scientist supervisor, entrusted with the latent print unit at the Denver Colorado Police Department. She oversees a team of four latent print examiners, two of whom wield expertise not just in latent prints but also in the intricate field of footwear and tire examination.

At the core of their workflow lies the crucial element of lab requests. As an accredited laboratory, their process begins with a formal request for their expertise. The laboratory is a nexus where requests converge—some originating from crime scenes with evidence awaiting latent print development, while others stem from latent lifts, collected by crime scene experts.

Their toolkit is rich and varied. Central to their arsenal is the SPEX Forensics CrimeScope® CS-16-500W Multi-Wavelength Laser by HORIBA, a transformative device. This laser, a forensic light source illuminates evidence, unmasking latent prints on diverse surfaces, thereby aiding investigators in unraveling the intricate layers of criminal puzzles. The device's persistent use, averaging six to eight hours daily, attests to the instrument’s indispensable role in their operations.

The narrative unfolds as they grapple with two distinct aspects: chemically processing evidence and analyzing latent lifts. In the case of chemically processed evidence, their journey begins by developing latent prints on items recovered from crime scenes. These prints are then captured through digital photography, the images in some cases becoming crucial evidence. Meanwhile, latent lifts—prints collected by crime scene experts—emerge as latent potential waiting to be unveiled.

Their approach, characterized by swift precision, allows them to maintain an impressive four-day turnaround time for cases—a feat that diverges from many urban counterparts. Amidst the ocean of casework, they process an astounding number of latent prints annually, somewhere in the realm of 10,000 a year. Among these, around 4,000 latent prints of value beckon for comparison to their database of suspects, victims, witnesses, and civil records. Additionally, this team conducts chemical processing on approximately 1,600 items of evidence each year in an attempt to develop latent prints that may provide investigative leads for detectives.

The science of comparison takes center stage as they step into the arena of Automated Fingerprint Identification Systems (AFIS). This digital repository in Colorado holds a wealth of fingerprints—both civil and criminal, a dynamic reflection of society. When a latent print finds a potential match in AFIS, it triggers a process of analysis and comparison. The quest for matches extends beyond computer screens, as Williams’ team conducts manual comparisons, employing traditional methods that stand the test of time in cases where the AFIS system indicates a match and where detectives provide possible suspect names.

In the event of a latent print finding its origin, a process of verification ensues, a testament to its rigor and commitment to accuracy. However, the journey isn't always paved with successful identifications. When AFIS searches yield no hits, they plunge into the Denver Police Department's reporting system to unearth potential suspects.

The forensic labyrinth reaches its apex during courtroom trials. The science, while meticulously cultivated and well-established, faces the challenge of articulation. The method of analyzing, comparing, evaluating, and verifying (ACE-V), is steadfastly upheld. However, it's the methodology and the practice that often stand on trial, subject to relentless scrutiny. The science relies on the fact that, to date, no two individuals have been found to have the exact same fingerprints. This concept, rather than the measure of uniqueness, underscores the validity of their work—a powerful tool for the prosecution.

Throughout their journey, William’s team has woven a narrative that embodies the evolution of forensic science. The terminological shift from uniqueness to the absence of identical fingerprints reflects not just linguistic precision but also a commitment to transparency. The ever-expanding frontiers of scientific knowledge have dismantled the one discrepancy rule, the concept that one difference observed during comparison indicates exclusion, revealing the intricate nuances of skin behavior during print deposition.

Williams and her team, resilient in their pursuit of truth, stand at the crossroads of science and justice. As the complexities of forensic analysis continue to evolve, they serve as custodians of accuracy, ensuring that their work, while steadfast in its foundation, remains adaptable to the changing tides of science and the expectations of the legal arena.

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