AK Bassi, the officer investigating the CBI's number two Rakesh Asthana, has challenged in the Supreme Court his transfer to Port Blair, adding another to the pile of cases linked to the country's top investigating agency. Mr Bassi has also claimed in his petition that he has "incriminating evidence" against Rakesh Asthana, who has been accused of taking bribe from a businessman being investigated by the CBI. He told the top court a special investigation team or SIT must be set up to probe the bribery allegations against Mr Asthana.