The investigation into the coal scam reached its next stage with a court summoning former Prime Minister Manmohan Singh on Wednesday to appear before it on April 8. The Congress party rallied behind Singh, despite this fresh blow to the Gandhi dynasty that was in power till last year.

A special court under the Central Bureau of Investigation (CBI) ordered the 82-year-old Singh, billionaire Kumar Mangalam Birla and another official to appear on April 8, over accusations of criminal conspiracy and corruption in the illegal award of a coal field.

"I am upset, but this is a part of life," Singh told reporters in parliament. He is the second former prime minister to be summoned by a trial court, after PV Narasimha Rao in 1996.

Judge Bharat Parashar said in the summons that "a well planned conspiracy was hatched" to award Hindalco Industries a coal field in 2005 after its chairman Birla allegedly lobbied Singh, who was at the time acting as coal minister.

According to Reuters, Singh has not been charged with any crime but is being investigated for criminal breach of trust, criminal conspiracy, cheating and corruption, a prosecution lawyer said on condition of anonymity.

Most coal block awards made by Singh's government, which ran India for a decade, were overturned by the Supreme Court last year, which ruled the allocation process illegal. The scam known as ‘Coalgate’ came to light in 2012 after a government auditor said the exchequer had lost up to $33 billion due to collusion between officials and private firms to award coal-fields without auction.

The summons coincided with a debate in the upper House on a bill to allow coal-field auctions. Environment Minister Prakash Javadekar said the coal scam was a blot on the Congress and called on the party to end its opposition to the bill.

"I hope reason will prevail," Javadekar said. He denied any vendetta or political interference in the judicial process.

The Congress party, meanwhile, is putting its best legal minds together for Singh’s defence.

"We are fully behind him, we will fight this legally and with all the means at our command, we are sure that he will be fully vindicated," party president Sonia Gandhi told reporters on Thursday.

The top leadership of the Congress party walked to Singh's home on Thursday morning in a display of support for the former prime minister.

- Karan Singh

To Learn More:

Manmohan Singh must explain: how did a coal block reserved for the public sector land with a private firm? (by Supriya Sharma, Scroll.in)

Coal scam: Manmohan Singh becomes second former PM to be summoned under Section 319 (Economic Times)

Sonia Gandhi marches to support Manmohan Singh in coal field case (by Aditya Kalra and Frank Jack Daniel, Reuters)

Top Congress Lawyers for Manmohan Singh, Summoned by Court in Coal Scam Case (by Sandeep Phukan and Sunil Prabhu, NDTV)

CBI court summons ex-PM Manmohan Singh in coal corruption case (by Frank Jack Daniel and Krishna N Das, Reuters)