Former Union minister Dilip Singh Judeo and his personal secretary Natwar Rateria on Thursday appeared before the Central Bureau of Investigation for questioning in the cash-on-camera scam.

The CBI had asked the duo to appear before the agency after it had registered a preliminary enquiry into the case. The two had cited electioneering as one of the reasons for not appearing before the agency at that time.

They were again sent a notice on December 5 after which the two appeared before the agency for questioning today.

CBI sources told PTI that Judeo and Rateria were questioned 'partially' and the investigating agency would determine the future course of action into the case.

The duo would be questioned again, the sources said. It was, however, not immediately clear when.

The CBI would now decide whether to convert the preliminary enquiry into a regular case as the motive behind the bribe and the amount taken was not clear so far.

The CBI was also determining whether the videotape or the Video Compact Disc was genuine or doctored by getting it examined by the Centre for Forensic and Scientific Laboratory (CFSL).

The CBI would also ascertain as to who were present in the video footage besides authenticating the voice of those shown in it, the sources said.

The CBI was trying to find if there was any conspiracy to tarnish the image of the former minister, they said.

Rateria's questioning was the most crucial as he would help the agency in identifying other persons who were inside the hotel room when Judeo was allegedly being paid the bribe.

The first ever questioning in the cash-on-camera scandal was done on December 2 in which one person, Rohit Chaudhury, was quizzed after the CBI traced that some telephone calls were made from his number to the hotel room, where the video was shot. Questioning of the hotel staff was also done.

The CBI was also finding out the amount of bribe that was allegedly paid to the former minister and the favour sought in lieu of that.

Shortly after his questioning, Judeo said, "Whatever they wanted to ask me, they did and I gave them whatever information I had."