A 22-year-old man has allegedly told police he shot dead a technical college student on Monday morning because he stabbed one of his gang members.

Police arrested  Akarapol Sirimekanon, 22, and an 18-year-old male identified only as Thanakorn on Tuesday.

They are suspects in the murder of Pongpeera, a student at Dusit Technical College who was wearing his school uniform when killed on Monday morning.

The two suspects allegedly told police there were four of them and they had consumed kratom drinks before picking on the student. 

They said the victim was on his way to school, riding pillion on a friend's motorbike. The approached him on their motorcycles.

Mr Akarapol, who went to school in the Thon Buri area, said there was an argument and alleged that Pongpeera had stabbed Thanakorn, who was riding pillion on another motorcycle, so Akarapol shot the 16-year-old.

Thanakorn was a student at a technical college in Charansanitwong area.