Fire accident investigation is a systematic process used to determine how, where, and why a fire started, how it developed, and what factors contributed to its spread, damage, or casualties. A proper investigation helps identify the cause of the incident, establish responsibility where necessary, and develop measures to prevent similar fires in the future. The first step is to ensure the safety and control of the incident scene. Investigators should enter only after the fire has been extinguished and the area has been declared safe by the responsible authorities. Hazards such as structural instability, live electrical systems, toxic gases, hazardous chemicals, and hot surfaces must be identified and controlled. The scene should also be secured to prevent unauthorized persons from disturbing evidence. The next step is to preserve and document the fire scene. Investigators should establish a controlled perimeter and restrict unnecessary movement. Photographs, videos, sketches, measurements, and notes should be made before evidence is moved or removed. Important features include burn patterns, fire damage,