Three stun guns, believed to be destined for sale to robbery gangs, were seized by police as they arrested a suspected top triad in an ambush in Mongkok yesterday. The raid came after a tip-off two weeks ago that the flat where the man was captured was being used to hide weapons, according to a police source. Two of the stun guns were being carried in a bag by the 29-year-old suspect as he left the flat on the 11th-floor of a building in Kam Lam Street. He was intercepted by officers from the Kowloon West regional crime unit at about 7.30am. The other stun gun and two knives were found in a drawer when 14 officers raided the flat. 'The suspect is an alleged office-bearer of the Wo Shing Wo triad society,' the source said. 'He is believed to be the core member of a syndicate that supplies stun guns to local criminals to carry out robberies.' It is understood the suspect was active in Mongkok, Yau Ma Tei and Tsim Sha Tsui. He was allegedly involved in 'quick cash' crimes and extortion. Police believe they have thwarted a number of planned robberies with the seizure. Detectives were reportedly told that the three weapons were smuggled into Hong Kong from the mainland. The weapons, which release a high-voltage shock and are classified as firearms in Hong Kong, could render a victim unconscious and cause cardiac arrest. Senior Superintendent Ip Wai-keung of the Kowloon West crime unit said police were concerned about an increasing number of stun guns seized over the past two years. He said they would closely monitor the situation. Two months ago, police arrested a 45-year-old man and seized a stun gun and a pistol loaded with three rounds of ammunition in Minden Row, Tsim Sha Tsui. Officers made a record haul of 12 stun guns when they raided a Kimberley Road cooked-food stall in Tsim Sha Tsui and arrested a 30-year-old man and his father, 60, in January last year. The three stun guns seized in yesterday's operation have been taken to the Electrical and Mechanical Services Department for examination. The 29-year-old man, who was arrested for possession of firearms without a licence, was being held for questioning last night.