undercover officer posed as a struggling debtor and was allegedly robbed by Hells Angels gang members in a police sting targeting unlawful debt collection. Court documents show a special duties constable with an assumed name of "William Baker" was allegedly robbed of a Toyota Hilux by four men working as debt collectors. The sting was part of a long-running operation against organised crime and led to criminal charges for three Hells Angels members and an associate. Police raided properties in Helensville, Manukau and Auckland city on Friday and arrested the patched trio of Andrew Joseph Sisson, 51, Kishor Chandra Singh, 40, and Wayne Brendon Franklyn, 39. They say they found three rifles and 650 bullets at Sisson's Helensville home. A fourth man, 21-year-old Nathan Scott Hampton-Burgess, was also arrested after complaints about debt collection agencies Dirty Debtors and Rapid Recovery. All four men were charged with participating in an organised criminal group and the aggravated robbery of "William Baker" on Friday in the police sting. Sisson was also charged with possession of three rifles - a Ruger bolt action .243, a Ruger bolt action .308 and a .22 rifle - and 650 bullets. The senior Hells Angel was also charged with robbing a Helensville couple of a Suzuki quad bike in March and the theft of a Toyota van in September under the guise of recovering debts for clients. He was also charged with using a document headed "Warrant to Repossess" with intent to obtain property dishonestly. Sisson, who will appear in North Shore District Court today to apply for bail, is the man behind Dirty Debtors Ltd. The debt collection firm runs a website to "name and shame" people who allegedly owe debts to clients. Detective Inspector Grant Wormald, of the Organised and Financial Crime Agency New Zealand, said some debt collectors traded on their gang membership. "More often than not the gangs are used to collect debts in the knowledge that people will pay up through fear and intimidation," he said.