Bhupender Singh Patel alias 'Rahul' appeared before the Central Bureau of Investigation for questioning in the cash-on-camera scam involving former Union minister Dilip Singh Judeo.
Patel came to the CBI headquarters in New Delhi along with his two lawyers, sources said.
Patel claimed that he was a journalist and had carried out a sting operation against Judeo. He added that before the scandal broke out Judeo had taken bribe from him many times.
The sources said that he was likely to hand over to the agency three videotapes and an audiocassette in which he had caught Judeo's deals.
Patel had filed a petition before the Delhi high court seeking quashing of the CBI first information report against him. The court, however, asked him to join the investigations but told the CBI not to arrest him till February 17, the next date of hearing.
The CBI will also take his voice sample and match it with the voice in the videotape that shows Judeo allegedly receiving Rs 900,000.
