Jakkrit Panichpatikum fired the gun inside his home and then assaulted his wife and mother, the Bangkok Post reported Monday.
Panichpatikum, who competed in the 2012 Olympics in London, was arrested Saturday at the home of a friend after promising to surrender to police Friday following the Thursday incident.
He was initially charged with attempted murder, assault, illegal possession of firearms and committing violent acts. Police filed additional charges Monday of resisting a blood test to determine if he had used drugs and intimidating others.
Police said they would ask a court to refuse bail for Panichpatikum because he owned more guns, had allegedly intimidated witnesses and had attempted to flee.
Panichpatikum's wife, Nitawadee Pucharoenyos, and mother, Bunchit Panichpatikum, also said they opposed his release, fearing for their safety. His wife said her husband's addiction to drugs had worsened since competing in London.