Corporate lobbyist Niira Radia  met CBI Director A P Singh as the agency prepares a second supplementary charge sheet in the 2G scam which is expected to be filed in the next few weeks.

Both Radia and CBI remained tightlipped on the purpose and the outcome of the meeting which lasted 20 minutes. Radia also met the home ministry officials.

"She is a witness in the case and can meet any official of the agency," CBI sources said.

CBI is likely to file the second supplementary charge sheet in the scam by June end or in first week of July, the sources said.