Seven mainland men believed to have come to Hong Kong to commit crimes were arrested yesterday after police raided a flat in Shamshuipo and seized a stun gun and an air pistol. One of the men allegedly tried to escape by jumping out of a window of the second-floor flat in Ki Lung Street when anti-triad officers from Kowloon West regional crime unit broke in at about 6am. The man, 30, landed on the first-floor canopy and was injured in the fall, police said. He was treated for leg injuries at Caritas Medical Centre. The other six men, aged between 21 and 30, were arrested in the flat. 'A preliminary investigation showed that the gang came to Hong Kong to commit crimes,' senior Superintendent David Ip Wai-keung said. Seizures of stun guns had been increasing this year and police were determined to crack down on crimes related to firearms, he added. The seven were put under surveillance after they arrived in Hong Kong about a week ago. 'They claim that they are second-hand electrical appliance traders and came to Hong Kong to purchase goods,' a police source said. The men, arrested for possession of firearms without a licence, were being held for questioning last night.