Investigative sources say Tokyo police have decided to ask a former counselor at the Embassy of Singapore in Japan to turn himself in on suspicion of secretly filming a naked male junior high school student at a public bath in the Japanese capital in February this year.

The sources say the 55-year-old former counselor is suspected of covertly filming the 13-year-old with a smartphone in the changing room.

An employee of the bathhouse thought the man was acting suspiciously and called the Tokyo Metropolitan Police Department. Officers who rushed to the scene checked the man's smartphone and found footage of the student and other naked images.

Sources say that during questioning by officers, the former counselor admitted that he filmed the video to watch it later by himself.

But he refused officers' requests to voluntarily accompany them to the police station, or submit his smartphone.

He reportedly deleted all the images on the spot at the request of the student's parent.

Sources say the former counselor told the police he had taken images about five times at the bathhouse.

The man has reportedly been removed from his post. The website of the Embassy of Singapore says that a counselor is a senior diplomat.

Tokyo police are investigating the case on suspicion of violations of laws banning child pornography and others.

They have reportedly decided to ask the man to turn himself in through Japan's foreign ministry, as he has diplomatic immunity from arrest until he leaves the country.

The police are also considering sending papers on the case to Japanese prosecutors.