The importance of chemistry in forensics is best said by the American Chemistry Society's article on Forensic Chemists:
"On an average day, forensic chemists apply knowledge from diverse disciplines such as chemistry, biology, materials science, and genetics to analyze evidence found at crime scenes or in the bodies of crime suspects. Forensic chemists often don’t know the nature of the sample before they analyze it. As a result, they use criminalistics, the qualitative examination of evidence using microscopy and spot testing, and analytical toxicology that looks for evidence in body fluids through a range of instrumental techniques from optical methods (UV, infrared, and X-ray spectroscopy) to separations analyses (gas chromatography, HPLC, and thin-layer chromatography)."
Subtopics in forensic chemistry include serology, toxicology, pharmacology, and ballistics analysis.
Forensic chemistry is very closely linked to forensic biology and therefore shares many of the same fields of study.
