The Supreme Court on Friday pulled up the Delhi police in connection with the 2008 cash for votes scam, saying it was giving the latter four weeks (one month) to find the source from where the money had originated.
The cash-for-votes scandal relates to the ruling United Progressive Alliance allegedly bribing lawmakers to survive a confidence vote on July 22, 2008.
The vote in the Lok Sabha arose after the Communist Party of India-Marxist-led Left Front withdrew support from the government, who wanted to pursue an Indo-US nuclear deal.
The CPI-M had objected to a proposal that would see the United States supply nuclear technology to India in return for India agreeing to United Nations inspections of its nuclear programs and the splitting of the civil and military aspects of those programs.
The CPI-M believed that this would cause India to be effectively subservient to the United States.
The opposition Bharatiya Janata Party also objected to the proposal on the ground that the inspections could impede development of the country's nuclear arms program.
The vote was won by the government in the face of the predominantly left-wing and Hindu nationalist objections.
It was argued that the nuclear infrastructure needed to be developed more rapidly because the existing electric generation facilities were incapable of meeting growing demand.
The government's success in the 2008 confidence vote was marred when three BJP MPs, including Ashok Argal, waved bundles of cash which they produced from bags in parliament during the debate, accusing the government of giving it to them in order to buy their support or abstention in the vote.
The BJP demanded the resignation of Prime Minister Manmohan Singh over the allegations and claimed that they had video evidence of the deals being made.
A CPI-M leader said that "Practically every member of parliament had been approached with offers of money and inducements."
The government denied the allegations, pointing out that Argal would have self-incriminated himself by admitting to receiving a bribe.
The then Speaker of the Lok Sabha, Somnath Chatterjee, had asked Delhi police to investigate the matter.
On August 2, 2008, the BJP offered "documentary evidence" to support its allegation that Argal, Faggan Singh Kulaste and Mahaveer Bhagora had been bribed.
The evidence included transcripts of video recordings and explanatory letters from two of the MPs, all of which was passed to the investigatory committee that had been set up by parliament.
The BJP also criticised television channel CNN-IBN, who had recorded the BJP MP's attempt to sting the government but had not broadcast it.
The tapes were broadcast on August 12, 2008 after CNN-IBN had made its appearance before the investigating committee.
Parliamentary investigation began on July 30, 2008 and has frequently been referred to as the Kishore Chandra Deo Committee.
The committee reported in December 2008 that it had found no evidence of bribery in the case of Rajya Sabha members Amar Singh and Ahmad Patel.
They had been accused of offering the bribes. Singh was then a prominent member of the Samajwadi Party which had begun to support the government at the time when the Left Front moved to oppose it.
The committee also recommended further investigation into the activities of Sanjeev Saxena, Sohail Hindustani and Sudheendra Kulkarni.
Saxena was an aide to Amar Singh, Kulkarni had a similar role with BJP leader L. K. Advani and Hindustani was a Bharatiya Janata Yuva Morcha activist.
Some committee members distanced themselves from the report's full conclusions, but agreed that the additional investigation was needed. A police investigation was instigated in January 2009 to look into the issues relating to Saxena, Hindustani and Kulkarni which had been recommended in the report of the parliamentary committee.
