Delhi Police has interrogated interrogating Rajya Sabha Member Amar Singh in the cash-for-vote scam. Former General Secretary of Samajwadi Party, Amar Singh is accused of sending bribe money to win over three BJP MPs during the 2008 trust vote. Earlier, Delhi Police issued summons for his appearance before the Crime branch.The decision to call Amar Singh for questioning comes after the arrest of Suhail Hindustani, who allegedly acted as a liaison between Singh and BJP MPs. Delhi Police already arrested Sanjeev Saxena in the case on 17th of this month. He was once considered close to Mr. Amar Singh.Delhi police have speeded up the arrests and fresh investigations into the case after the Supreme Court strongly criticized the police last week for its callous approach and tardy progress in the case.