The protesters were taken aboard helicopters and transported to the Border Police Patrol Region 1 headquarters in Pathum Thani’s Khlong Luang district for questioning, reports said.
Pol Maj Gen Smith Mukdasanit, commander of Pathum Thani provincial police, is in charge of the investigation.
Security at the police compound has been put on high alert and barricades have been placed at entrances to prevent outsiders from entering the premise.
The Centre for the Administration of Peace and Order has reported that a police officer succumbed to his injuries at the Police Hospital after being shot in the chest during the clash at the sports complex. At the same location, two other policemen were injured by ping pong bombs.
According to reports by the Ministry of Public Health, 96 protestors were injured and four are in a critical condition in the aftermath of the conflict.