He said he heard the sound of gunfire, prompting him to run behind Polenghi to the scene and investigate.
He said he videotaped the unfolding incident, including the fall of Polenghi after gunshots were fired from the area occupied by security forces.
The prosecution had submitted his videotape as evidence.
The next hearing is scheduled for January 25. The court is expected to conclude the inquest by the middle of next year.
The victim’s sister Elisabetta Polenghi said she expected justice to prevail. She voiced her confidence in the Thai judiciary, saying the courts had ruled in the four previous inquests that victims were killed by gunshots fired from the soldiers.