When examining a crime scene investigators rarely discover a smoking gun--figuratively or literally. Rather they are more likely to find gunshot residue an aging bloodstain a piece of fiber a suspicious white powder or some unknown chemical substance that requires thorough testing and analysis to prove useful to the criminal justice process. That's where forensic chemists come in. On any given day a forensic chemist may be asked to examine human tissue to look for poison or drugs analyze charred wood from a fire scene to uncover fire accelerants or test rubble from the site of an explosion to determine what volatile agents were used. With their specialized knowledge and skillset forensic chemists can apply a variety of scientific techniques and instruments to identify unknown substances found at crime scenes and extract other data which turns the microscopic remnant into a valuable clue for understanding what happened when where and by whom. This circumstantial evidence and the forensic chemist's expert interpretation of it are critical not only to investigating crimes and tracking down potential suspects but also to rigorously prosecuting offenses and providing juries and judges with objective information they can use to make informed decisions when carrying out justice.