Upon receiving a report of the 11.30am shooting at the school on On Nut-Lat Krabang Road in Prawet district, police arrived at the administrative office near a kindergarten classroom where the shooting occurred.

An initial investigation concluded that school principal Pisitpol Kraipipat, 48, shot his sister Piyarat Surapongprapa, 45, the school’s general manager, six times and she sustained wounds to the neck, left leg and right shoulder.

Piyarat is in critical condition at Sirindhorn Hospital.

Witnesses told police that Pisitpol had showed up at the office appearing drunk and started arguing with personnel. He pulled out a pistol when his sister Piyarat tried to intervene and began shooting before fleeing in a Mitsubishi Mirage.

Police have launched a manhunt and were interviewing witnesses as of press time.