Police are investigating a triad gang that is believed to have controlled three red minibus routes and pocketed at least HK$14 million a year as protection fees from drivers. The investigation came as an alleged former dragonhead of Wo Shing Wo triad society, who stepped down last month, was arrested along with two others on Sunday for laundering more than HK$4 million in protection fees from about 30 minibus drivers. Police believe the 47-year-old man, surnamed Poon, known as 'Broken Mouth Bun', was the leader of an extortion gang that controlled a red minibus route running between Tsuen Wan and Kwun Tong. Yesterday, a senior police officer said investigation showed that three other minibus routes running between Tsuen Wan and Kowloon East - Choi Hung, Tsz Wan Shan and Ngau Tau Kok - are being controlled by another Wo Shing Wo gang. 'Each route involves about 30 drivers and each driver pays at least HK$10,000 a month as a protection fee to the triad gang,' the officer said. Despite the payment of the fee, each driver could still earn between HK$10,000 and HK$20,000 a month. 'They were guaranteed a steady income because the gang made sure no other driver could run these routes,' the officer said. 'So none of the drivers were willing to come forward and report such illegal activities.' Anti-triad officers from New Territories South crime unit were collecting evidence against the gang. So far, no one else has been arrested. Tsuen Wan is traditionally a Wo Shing Wo stronghold, but it has extended its influence to Tsim Sha Tsui and Mong Kok. Its dragonhead is elected every two years. 'Broken Mouth Bun' is the former leader, who stepped down last month. He has been replaced by another gangster known as 'Shu Tsai'. The triad is known to be involved in extortion, drug trafficking, gambling and prostitution in districts such as Tsim Sha Tsui, Mong Kok, Tsuen Wan, Tai Po and Sheung Shui, according to police. On Sunday, Poon, his 51-year-old ex-wife and a 44-year-old woman were arrested by police on suspicion of laundering the protection fees collected from about 30 minibus drivers running between Tsuen Wan and Kwun Tong. Yesterday, the trio were released on bail after being detained for questioning. No one has been charged. Police said officers needed more time to investigate the case. During the raids at three homes in Tuen Mun and Tai Kok Tsui, police seized about HK$1 million in gold ornaments, luxury watches, jade rings and cash. Police believe the valuables were bought with the proceeds of the extortion scam that had been in operation since 2006. 'We will consider applying to the court to freeze the assets owned by the three suspects and linked to the extortion scam,' the officer said. Unlike green minibuses, red minibuses do not serve designated routes at fares approved by the Transport Department. Instead, they operate flexibly around the city. There are about 1,300 red minibuses, running more than 200 routes.