Senator Boonsong Kowawisarat reportedly had in his possession a loaded 9mm Uzi submachine gun, though it is unclear why.
According to police, the shooting took place inside a restaurant in the northern province of Phrae. The 55-year-old politician drew his weapon while he and his secretary, 46-year-old Chanakarn Detkard, were waiting to be served. The Uzi suddenly went off, and a bullet struck Chanakarn in her stomach.
She was rushed to the hospital by the restaurant owner while Boonsong remained behind in shock.
Due to his parliamentary privilege, the Senator has yet to be charged, but police expect he will ultimately be tried for death by negligence.
If convicted, Boonsong faces as many as 10 years behind bars.