Police are probing the case of an officer who was photographed kneeling and holding up a sign bearing the words “SORRY SIR” at a police station in Kowloon.

Photos of the male officer went viral on social media on Tuesday. Dressed in uniform, he is seen holding an A4-size sign printed with the words “SORRY SIR,” in English, in the carpark of Kwun Tong Police Station.

Apple Daily reports that the officer is a senior police constable and has been serving the police force for 20 years.

It is understood the officer had an argument with his supervisor over a miscalculated HK$700 (US$89) over-time allowance when he was stationed in Tseung Kwan O, in 2013. The supervisor wanted to pay the officer back with his own money but the latter refused.

The officer later complained to senior management about the supervisor’s handling of the matter, a police source was quoted as saying.

The dispute was later resolved and it was understood that another supervisor told the officer to apologize. The officer did not follow that instruction.

The officer was later deployed to Kwun Tong – and his former supervisor was also deployed to the same station in August of this year.

Since then, it is reported that he has been spotted several times standing silently in the carpark, facing the supervisor’s office, even in the rain.

In light of the officer’s unusual behavior, he had been demoted to the role of supporting officer and is not allowed him to carry gun.

HK01.com reports that a police spokesperson confirmed the incident happened at noon on Monday. They said the matter was being followed up that the officer would be provided with any support necessary.