If the top court confirms Mr Sidhu's conviction, handed earlier by the high court, he stands disqualified immediately as a lawmaker. After serving his sentence, he would not be able to contest elections for another six years.
The 54-year-old was initially acquitted in the case in September 1999. But the high court had reversed the verdict in 2006. Mr Sidhu was found guilty of causing accidental death and was handed a 3-year-jail term and a fine of Rs 1 lakh.
The next year, the Supreme Court put the high court's decision on hold.
Mr Sidhu had allegedly hit a 65-year-old man, Gurnam Singh, on the head during an argument over the parking of a car in Patiala in December 1988. The police claimed he fled after the attack. Gurnam Singh died in hospital.
Mr Sidhu had joined the Congress in the run-up to the Punjab Assembly elections. He was seen as a contender for the post of the deputy of Chief Minister Amarinder Singh, a bitter rival from his BJP days. The former cricketer was finally given the tourism portfolio.
Mr Sidhu had quit the BJP after the party decided to field Arun Jaitley from Amritsar - the seat the former cricketer won twice - in the 2014 polls.
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