Present and former students from one school were behind the indisciminate attack on a freshman university student on Saturday that led to the death of a teacher from a wild shot, according to investigators at Bangkok's Metropolitan Police Bureau.
The wild shooting was attributed to interschool rivalry, not a personal conflict between students.
Metropolitan chief Pol Lt Gen Thiti Sangsawang said on Tuesday the attack was carried out by a gunman in a full-face helmet riding pillion on a motorcycle, but more than two people were involved in the planning.
Several shots were fired indiscriminately. Nineteen-year-old Thanasorn Hongsawat, a first year student at Rajamangala University of Technology Tawan-Ok, Uthenthawai Campus, in Klong Toey district was severely wounded.
An innocent woman, Sirada Sinprasert, 45, who taught computer science at Sacred Heart Convent School, was killed by the first shot, which missed the intended victim.
She was hit and killed as she was about to use a bank ATM near her school.
Pol Lt Gen Thiti said there were more than two people behind the well-planned attack, and present and former students from a single school were involved.
The gunman and his driver used a stolen motorcycle which was repainted after the crime to facilitate their escape. They also changed their clothes to make tracing them more difficult.
Detectives were tracking down the two suspects and believed they had left the capital, the Bangkok police chief said. They had information from a school and expected to arrest them in the near future.
"The attack stemmed from school rivalry. The attackers and the victim had no personal conflict," Pol Lt Gen Thiti said.
Pol Maj Gen Teeradet Thumsuthee, chief investigator, said the attackers did not look for a specific person, just fired indiscriminately at another student. He also said their escape was aided by present and former students of one school.