Testifying as the only defense witness in Eastern Magistrates' Courts before magistrate Jason Wan Siu-ming yesterday, Choi - who is not charged with any offense - said he first visited Viet Spa in Wan Chai in mid-2020 and that he had been there four to five times. And the last time was a week before the raid on March 19 last year.

Choi, 51, was caught in a massage room by officers, who also arrested three women and a man. The three women - masseuses Li Yi-qing, 36, and Zhang Mingfang, 35, and Vietnamese Nguyen Thi Thu Huong - were each charged with one count of managing a vice establishment.

Li and Nguyen faced another joint count of managing an unlicensed massage parlor.

Wu Ping-hung, 61, was charged with one count of managing a vice establishment and another count for managing an unlicensed massage parlor. They all had pleaded not guilty to their charges.

The court has heard that undercover officers visited Viet Spa thrice between October 2020 and March last year. One of the officers told the court he was offered a range of sexual services - including masturbation and nuru, a Japanese form of sensational massage - priced between HK$500 and HK$800.

Choi gave the magistrate a 90-degree bow upon entering the courtroom. During testimony he appeared calm and looked at barristers in the eye when answering questions.

Asked how many times he had visited Viet Spa, Choi initially said he couldn't remember specifically. "Perhaps several times," he said. He eventually said he had been there four to five times under repeated questioning.

Choi said he accepted "the same service" in a room with a woman for an hour every time he visited, adding he had not requested to be served by a specific masseuse.

He said he could not recall whether he had met the woman who was in the room with him during the police raid, but added she had never offered him sexual services nor had anyone made such offer to him.

Choi said there were no signs or notices on the provision of sexual or masturbation services in Viet Spa and that he did not believe the parlor would offer such service to him.

Choi said he visited Viet Spa "in a personal capacity" unrelated to his police duties and that he had no idea about the anti-vice operation.

He agreed with the prosecutor's remarks that he did not know whether Viet Spa was licensed and that all his inquiries to the parlor were only related to massage.

Choi said his knowledge about the parlor had come from his personal judgement based on the public area and rooms that he had been, and that he had no idea if masseuses offer other services to other customers.

He said he did not know any employees or manager at the parlor nor had he investigated their backgrounds.

Choi - whose testimony lasted less than an hour - said he is now senior assistant police commissioner and head of department for personnel and training. He was the city's first director of police national security department when it was established in July 2020.

Choi was put on leave for about five months between March and August last year before being reassigned.

Wan adjourned the case to September 23 for closing remarks. The four defendants remained out on bail.