Hong Kong police are investigating an allegation that a four-year-old boy was indecently assaulted at an international school in Stanley, with the institution saying its security footage showed “no evidence of any wrongdoing” on the day of the suspected incident.

A source said on Wednesday that the International Montessori School kindergarten pupil complained to his family that his buttocks were sore on April 17 after his mother picked him up from school.

His father, who suspected that the child had been indecently assaulted, took the boy to Gleneagles Hospital in Wong Chuk Hang for a medical examination and reported the matter to police.

The insider said the medical examination found redness around the boy’s buttocks.

The source said police had classified the case as “indecent assault of a male under 16”, with the Western district investigation team tasked with following up.

In a statement on Thursday, the International Montessori School said it had reviewed records and closed-circuit television footage after learning of the allegation.

“We can confirm that this video footage from that day shows no evidence of any wrongdoing and that there was no evidence of any periods when the child was left unaccounted for,” it said.