A Delhi government clerk, suspected to be the mastermind of a crime syndicate helping candidates cheat the online examination conducted by the Staff Selection Commission, has been arrested here, police said today. With the arrest of Harpal Singh, 33, on Friday, the total number of gang members arrested in the case has reached 10. An upper division clerk in trade and tax department, he had been on the run since the syndicate was busted in March. Singh was the main driver behind the gang, who had planned the process to cheat the computer-based examination, police said. The gang members used to assist candidates via a remote-access application, Team Viewer. Last month, Delhi Police arrested five persons in connection with the matter. Another four were arrested in March, when the case was transferred to the crime Branch from the north district police. During interrogation, the police found that the syndicate worked as a organised grouping. The members would hack into the online system and assist candidates taking the examination. The candidates were charged between Rs 5 and Rs 10 lakh. The gang allegedly had developed a network with examination centres and computer labs in various cities. The SSC outsources the conduct of the examination to labs such as these. Singh and other gang members also used to run such labs in parts of Delhi, the police previously said.