New Delhi, Jul 20 (IANS): An alleged middleman in the cash-for-votes controversy related to the 2008 trust vote Wednesday said Rajya Sabha MP Amar Singh was the "main" man behind the scandal and also accused Ahmed Patel and other Congress leaders of involvement.

"I have nothing to hide, Amar Singh has the main role in this," Suhail Hindustani told reporters Wednesday after being questioned by the Crime Branch of Delhi Police.

"Amar Singh had used Ahmed Patel in all this," he said, referring to the former Samajwadi Party leader and the confidant of Congress president Sonia Gandhi respectively.

"Amar Singh and Ahmed Patel were working together and I helped them. There is nothing left in this case, it's crystal clear," he said.

Hindustani, who claims to be a former Bharatiya Janata Party (BJP) youth wing member, also said he was called by those "close to" Prime Minister Manmohan Singh.

"Ahmed Patel called me, big leaders of Congress called me, people close to (Prime Minister) Manmohan Singh called me," he said.

He also said that a narco test should be conducted on everyone to find out the truth.

"Do my narco test, do Amar Singh's narco test, if possible do Manmohan Singh's narco test," Hindustani said.

The questioning of Hindustani came a few days after Amar Singh's former aide Sanjeev Saxena was arrested by Delhi Police.

Saxena is alleged to have tried to bribe BJP MPs Ashok Argal, Mahavir Bhagora and Faggan Singh Kulaste into voting for the Manmohan Singh government in the 2008 trial of strength over the Indo-US nuclear deal.

Bags filled with currency notes were shown in the Lok Sabha on July 22, 2008, minutes before a trust vote was to take place.

Hindustani was called to the Crime Branch office this morning for questioning, where he appeared with supporters and a bouquet of flowers for the senior official questioning him.