The 23-year-old ringleader allegedly persuaded three friends to don masks and storm the school in the town of Siem Reap Thursday morning, herding a teacher and about 30 children into a classroom.
Police say the men, all in their early 20s, wanted to extort money from the foreigners and well-off Cambodians whose children attend the school near the famed Angkor Wat temple complex — the biggest tourist attraction in this impoverished country. The children, aged from about 2 to 6 years, came from about 15 countries.
The alleged gang leader said he initially planned the raid as revenge against a South Korean man who employed him to drive his two children to the school, said Prak Chanthoeun, deputy commander of military police in Siem Reap province.
The suspect said his employer recently got angry with him and slapped his face, causing him to quit his job and return to his hometown in the central province of Kandal.
"Every day, he thought about taking revenge against the South Koreans. So he bought a pistol, then called three friends from his home area," said Prak Chanthoeun.
He then "proposed that they go to the school, find the two Korean children and kill them. But when they arrived there, they didn't see the Korean children," he said.
Ou Em, head of criminal police division in Siem Reap, said police plan to charge the suspects with "illegal detention of persons and kidnaping for ransom."
He said the four are expected to appear in court Saturday. A fifth man was also arrested on suspicion of involvement even though he was not at the scene Thursday.
Police described the four as small-town gangsters looking for easy money.
"They learned there were the children of rich foreigners at the school," said Prak Chanthoeun.