What does soot in or around the mouth of a deceased victim indicate?

Soot in or around the mouth of a deceased victim strongly indicates that they were actively breathing while the fire was occurring. This presence suggests that the victim inhaled smoke or particles, which typically occurs when an individual is conscious and attempting to breathe in an environment filled with smoke from a fire.

When a fire starts, it produces smoke and toxic gases, and if the victim was present and breathing, soot could easily be deposited in the oral cavity and surrounding areas. This can help forensic investigators confirm that the victim was indeed at the scene during the fire event rather than being unconscious or absent, as those circumstances would typically prevent the intake of soot.