One of Hong Kong’s top policemen gave a literal thumbs up to one of his officers the day after she opened fire on a knife-wielding man in an MTR station, despite calls for an investigation into her decision to shoot in such a crowded place. Photos circulated among officers after the director of operations, Chris Tang Ping-keung, tipped to be the next police chief, visited the officer, surnamed Yuen, and three colleagues at the Police Tactical Unit Kowloon West operational base in Shek Kip Mei at noon on Thursday. A police spokesman said the gesture signified support for the officers involved as they endured tremendous pressure after the incident, and did not mean management was taking a side on the issue. “It is necessary for the senior officer to cheer the group up and boost morale as they have gone through such a dangerous episode,” the spokesman said. “One must shoulder huge pressure after firing rounds while on duty.” Tang and the four officers, who were involved in the fracas in Sham Shui Po MTR station on Wednesday , gave a thumbs up in the picture. At about 7.40am that day, Yuen and her partner picked up a 55-year-old builder, surnamed Chow, as he appeared suspicious. During questioning, the officers said, Chow took a 15cm cutter from his backpack. Chow waved the weapon and repeatedly tried to attack the duo, despite a verbal warning, police said. Yuen, a six-year veteran, shot him in the abdomen. Police to investigate reports of mainland tour agents operating illegally On Thursday morning, investigators revisited the MTR station to look for witnesses. Chow remained in critical condition after two rounds of surgery. Lawmakers across the political spectrum had questioned whether it was appropriate to fire a gun in an MTR station. They urged a thorough and transparent investigation. The force said in a statement on Wednesday night that initial investigation had cleared Yuen of any breach of guidelines. “The officer acted in accordance with the guideline and the circumstance. She made a correct decision to prevent serious bodily harm and had eased a violent crime,” the statement read. Tang is to receive a report on the event within 48 hours of the incident. According to the Police General Orders, officers are allowed to fire under three circumstances: to protect anyone, including themselves, from death or serious injury; to bring about the arrest of a person who has just committed a serious or violent crime; or to quell a riot or insurrection.