The opposition BJP leaders tried to lay siege to the chief minister's office-cum-residence here on Wednesday alleging rampant corruption by the ruling Congress government in Karnataka, but were stopped and taken into preventive custody. The party leaders, including BJP state president B Y Vijayendra, Leader of Opposition in the Karnataka Assembly R Ashoka, former ministers S Sunil Kumar, Araga Jnanendra, S Suresh Kumar, C N Ashwath Narayan and C T Ravi were accompanied by several MLAs and a large number of party workers. Due to the heavy deployment of police forces, the BJP leaders could not reach their destination and were taken under preventive custody. The party has alleged that there was around Rs 4,000 crore worth of alternative sites (plots) scam in the Mysuru Urban Development Authority (MUDA) in which one of the beneficiaries is Chief Minister Siddaramaiah's wife Parvathi. The party also charged that there were attempts to cover up over Rs 180 crore Maharshi Valmiki Schedul