Experts | Forensic Analytical Crime Lab

Experts &
Staff

Biology/DNA Team

David Hansen, M.S.

DNA Section Technical Leader

Mr. Hansen specializes in human biological evidence analysis using advanced PCR-based STR techniques, including autosomal (GlobalFiler) and Y-STR (Yfiler Plus) analysis. He led the implementation and validation of probabilistic genotyping with STRmix and has extensive experience in criminal and civil casework.

Curriculum Vitae

Nancy Dinh, M.S.

Senior DNA Forensic Scientist / QA Manager

Ms. Dinh has a decade of expertise in biological evidence screening and DNA analysis using STR and Y-STR PCR techniques. She has extensive experience in criminal, civil, and post-conviction casework and is available for expert consultation, case review, and court testimony. Outside of casework, she enjoys educating others about forensic DNA and mentoring aspiring forensic scientists.

Curriculum Vitae

Kristen Harty-Connell, M.S.

Senior DNA Forensic Scientist

Ms. Harty-Connell brings valuable experience from the Washington State Patrol and Montana State Crime Labs. She specializes in biological evidence analysis, including serology and DNA extraction, quantification, amplification, and interpretation. Kristy is proficient in forensic techniques, chemistries and robotics, and is court qualified as an expert in biological screening and DNA analysis.

Curriculum Vitae

Criminalistics Team

Chris Coleman, B.S., F-ABC

Senior Forensic Scientist

Mr. Coleman holds a B.S. in Forensic Science and brings 3 decades of experience with city and county law enforcement agencies. He is AFTE certified and court-qualified in firearms and toolmark examination, shooting reconstruction, crime scene processing, bloodstain pattern analysis, controlled substances, and latent prints. A Fellow of the American Board of Criminalistics. Chris regularly teaches firearms-related topics to law enforcement, legal, and medical professionals and instructs shooting reconstruction for the California Criminalistics Institute. He is a POST-certified Firearms and Force Options instructor and range master, and a past president of the California Association of Criminalists.

Curriculum Vitae

Alex Taflya, M.S.

Senior Forensic Scientist

Mr. Taflya brings over 25 years of forensic science experience including 22 years at the Contra Costa County Sheriff’s Crime Lab. He is court-qualified in crime scene reconstruction, bloodstain pattern analysis, trajectory determination, firearm identification, function testing, distance determination and serial number restoration. He also has expertise in forensic photography and trace evidence, including hair, fiber, glass, and physical match. Alex has both attended and led numerous training courses in firearms, trace analysis, photography, and crime scene investigation. He is an active member of AFTE, CAC, and AAFS.

Curriculum Vitae

Phil Hess, M.S.

Senior Forensic Scientist

Mr. Hess joins our team in 2026 with over two decades of experience working in an ISO/IEC 17025 accredited forensic lab where he specialized in Firearms and Toolmarks, Impressions (Footwear and Tire Tracks) Crime Scene Analysis, Bloodstain Pattern Analysis, Shooting Incident Reconstruction, and Forensic Photography. Phil holds professional certifications with the Association of Firearm and Toolmark Examiners in Firearms Evidence Examination and Identification, the International Association for Identification in Forensic Photography, and Foundational Knowledge in forensic science with the American Board of Criminalistics. He is a Past President, Life Member, and Distinguished Member of the California Division of the International Association for Identification (IAI) and served on the IAI’s Forensic Photography Certification Board. Mr. Hess was recognized with the California Association of Criminalists Paul Kirk President’s award for outstanding contributions to the field of Forensic Science.

Curriculum Vitae