Police, armed with a search warrant from the Criminal Court, raided a house in Nonthaburi’s Sai Noi district on Wednesday and arrested a suspect identified as Warongchai Kansri.
The suspect later provided clues, which led the police to five more locations in both Bangkok and Nonthaburi, where they arrested seven more suspects.
All eight were taken to the Metropolitan Police Bureau for questioning.
A police source said the investigators are not yet confident as to whether Warongchai was the one who fired at the student and teacher. The source said police are still interrogating the eight suspects for information to establish who were the gunmen.
The source added that Metropolitan Police chief Pol Lt-General Thiti Saengsawang would be present at the interrogation.
The eight suspects are accused of being involved in the November 11 shooting and fatally injuring Thanasorn Hongsawat, 19, a first-year student at Rajamangala University of Technology Tawan-ok Uthenthawai.
A stray bullet from that shooting killed Sacred Heart Convent School teacher, Sirada “Khru Jiab” Sinprasert, 45.
The arrest of the eight suspects came one day after police arrested another suspect in the capital’s Bangkok Yai district for allegedly shooting dead a 16-year-old technical college student in the Dusit district just before 9am on Monday. The weapon used in the Soi Ranong 2 killing was a pen gun.
The suspect was identified as Akkarapol Sirimekhanon, 22. He lives in Moo 6 village in Nonthaburi’s Sai Noi district but was in Soi Charalsanitwong 3 during his arrest.
Police said the suspect admitted to allegedly shooting the student, but claimed it was done in self-defence.
He was taken to the Dusit police station for questioning and legal action.
The 16-year-old victim, meanwhile, has only been identified as Pongpeera, a second-year technology university student.
On Wednesday, police also arrested a second suspect in relation to this case. The suspect, identified only as Thanakorn, was allegedly the pillion rider when Akkarapol allegedly shot Pongpeera. Police said Thanakorn, 18, claimed to have been injured in a knife attack by friends of the victim before he and Akkrapol decided to take revenge.