Police stormed a Hong Kong flat on Monday night, arresting a woman suspected of heading a triad faction and six alleged members in connection with the murder of a reputed gangster who died of injuries sustained in a bare-knuckle showdown in June.

The suspected leader of the Wo Shing Wo triad faction and her six alleged underlings were found hiding in a flat at the Regentville housing estate on Sha Tau Kok Road in the New Territories soon after 9pm. A force insider said he believed the group had been using the flat as a hideout for more than a month.

“Officers had to break into the flat as they refused to open the door,” the source said. “Some of the suspects put up a struggle but were eventually subdued.”

He said no officers were injured in the incident.

The source said an investigation suggested the woman, aged around 30, had not taken part in the fight two months ago that led to the man’s death, but had called in her followers to engage in the brawl.

The seven suspects were wanted by police in connection with the killing of a 27-year-old man who died on August 4 after spending weeks in hospital.

The victim, a suspected Wo On Lok triad member, had been helping the Wo Shing Wo gang run their illegal gambling and debt collection business, but was accused of stealing about HK$1 million (US$128,393) in proceeds.

In the early hours of June 26, in an effort to resolve the financial dispute, the man met the gang at a flat in a Tai Kok Tsui commercial building that he rented out as space for exercising, including boxing with friends.

The victim was granted the chance of a “free fight” to settle the alleged theft. Under the arrangement, he would have been able to walk free if he could beat the nine gang members present, one by one, in a fist-fight.

About an hour later, after defeating eight of the men, the victim finally succumbed to the blows and fell unconscious while fighting the ninth, but was not taken to hospital immediately.

Surveillance camera footage showed the victim was taken to Kwong Wah Hospital in Yau Ma Tei by taxi at about 9.30am that day. The case was reclassified as murder when he died in hospital on August 4.

Police believed the industrial unit where the brawl took place had been cleaned, as no blood stains were found and it smelled of antiseptic.

On June 29 and 30, two men were arrested in connection with the case. Then, on August 24, police arrested another two men in a Hung Hom hotel room and a Yuen Long village house. The 23-year-old girlfriend of one suspect, who was in the same hotel room, was also arrested on suspicion of assisting an offender.

Detectives from the Kowloon West regional crime unit are handling the case.