Here are the 10 big developments in the case:
The court set aside a closure report that the CBI had filed in 2009 and ordered it to record the testimony of all witnesses again, including three who had moved to the US after the 1984 riots.
Lakhwinder Kaur, the widow of one of the three men killed, had challenged the CBI's closure report pointing out that the investigating agency has not recorded the testimony of these key witnesses. It has been almost 29 years and many witnesses in the case have either become infirm or have died.
Congress spokesperson Renuka Chaudhury said after today's ruling that "if there is any proof against Jagdish Tytler, we will take steps against him." Meanwhile, Congress general secretary Digvijaya Singh strongly defending Mr Tytler said, "He has not been convicted yet. Why should he step down?" Mr Tytler is yet to comment on today's developments.
The CBI has already investigated the case twice. It had first filed a closure report favouring Mr Tytler in 2007. When the trial court rejected that, the CBI re-investigated the case and again in 2009, reported that it had found no evidence against the Congress leader.
The petitioners say they have lost faith in the CBI's integrity because of its repeated clean chits for Mr Tytler. They accuse it of shielding high-profile politicians.
The CBI has said in court that investigations show Mr Tytler was not present at the Pulbangash Gurudwara in north Delhi on November 1, 1984 when the three men - Badal Singh, Thakur Singh and Gurcharan Singh - were murdered by the mob.
The agency said Mr Tytler was at Teen Murti Bhawan, the residence of late Prime Minister Indira Gandhi, who had been assassinated by her Sikh security guards the previous day, October 31.
Another former Congress MP Sajjan Kumar too is facing trial for allegedly inciting a mob to kill Sikhs in the Delhi cantonment area. The CBI has concluded its arguments against him.
The riots began on the evening of October 31, 1984, the day Mrs Gandhi was assassinated. Over the next few days, more than 8,000 Sikhs were killed across the country, 3,000 of them in the national capital. Only 30 people in 12 murder cases have been convicted so far.
Ten different commissions and committees have looked into the 1984 Delhi riots in last three decades; 72 police officers were identified for connivance and gross negligence. The probe panels had recommended that 30 of them be sacked, but no action was taken.