Two triad groups are suspected of involvement in the attack in which veteran journalist Leung Tin-wai's arm was severed, police said yesterday. Nine men have been arrested in connection with the attack. Seven were being questioned last night and two had been released. The arrests began on Wednesday and continued yesterday. Mr Leung, 53, had his back slashed and left forearm and two thumbs severed in an attack by two chopper-wielding men in his Quarry Bay office in May. Superintendent Jimmy Leung Hung-wai said some of the suspects had triad backgrounds. It is understood Sun Yee On and Wo Shing Wo members were involved. It is thought the attackers were paid for the assault, believed to have been prompted by a personal dispute. But police said they were not dismissing other possible motives, including competition in the media and the content of the magazine. A journalists' group formed after the assault raised $5 million as a reward for the arrest of the attackers. Representatives will make a formal offer of the $5 million to the police today. Asked whether the money would be offered regardless of the motive for the attack, group member Lam Ping-hang said details would be discussed with police. But group spokesman Raymond Wong Yuk-man said the group was protesting against violence, whether or not it was provoked by a personal matter. Hong Kong Journalists' Association chairman Ivan Tong Kam-piu said he did not believe journalists had acted too quickly. He said: 'We expressed our concern about the whole incident. 'If it's personal, it's another thing,' said Mr Tong. Legislator Emily Lau Wai-hing said the motive for the attack did not make any difference to the community's response. 'It was because it was such a horrific act. That's why people felt such revulsion,' she said. Leung Tin-wai has taken the first steps to recovering the use of his left arm and two thumbs hacked off, but faces at least 18 months of work if all goes well, specialists say. His wounds have healed enough for him to undergo occupational therapy this week. But because his bones, nerves, tendons and muscles are still raw, three weeks after surgery, therapy has been slow to start.