Who He Is
For years, John Lentini investigated fires the way his colleagues did, trusting the same rules of thumb about how fires behave. He began his career in 1974 at the Georgia Bureau of Investigation’s crime laboratory, became a certified fire investigator in 1986, the year certification first became available, and has inspected more than 2,000 fire scenes. After a 1990 house fire in Jacksonville, Florida, he calculated it would take about 20 minutes for the fire there to reach flashover. To test the idea, he and others set a fire in an identical house two doors down, and flashover came in about four minutes. The test also showed that a fire set without any poured fuel could leave floor burn patterns that investigators usually mistook for signs of poured fuel, and it changed how Lentini saw his field.
Why He Matters
His research, including a 1992 study on cracked glass, helped overturn several long-held beliefs about how to spot a fire set on purpose. Lentini served on the National Fire Protection Association’s Technical Committee on Fire Investigations from 1996 to 2018 and helped develop NFPA 921, the Guide for Fire and Explosion Investigations. He wrote Scientific Protocols for Fire Investigation, a textbook now in its third edition. Courts have accepted him as an expert witness more than 200 times, and he now provides training and consulting through his company, Scientific Fire Analysis. In 2026, he published Twice Burned, a book about his 50 years as a forensic scientist and his work helping correct cases where people were wrongly blamed for fires.
