Alexandre Lacassagne (1843-1924), French forensic science pioneer. Trained as a doctor, Lacassagne devoted his life to developing a modern science of forensics. He was the first to study bloodstain patterns and bullet markings to identify murder weapons, and was an expert witness at numerous criminal trials. He also pioneered the study of criminal pathology, or a scientific account of the behaviour of criminals. For many years he worked as professor of forensic medicine at the University of Lyon, France.