Manjunath, 27, an Indian Oil Corporation employee, was shot dead on November 19, 2005.
The Supreme Court on Wednesday confirmed the life sentence of six people convicted of killing S Manjunath, an IIM-Lucknow graduate who took on the oil mafia in Uttar Pradesh.
Manjunath, 27, an Indian Oil Corporation employee, was shot dead on November 19, 2005, when he went to a petrol pump to collect samples and investigate reports of oil adulteration. His bullet-riddled body was found in a car.
The pump's owner Pawan Kumar, also known as Monu Mittal, is among those found guilty of murder. The five others are Rakesh Anand, Vivek Sharma, Devesh Agnihotri, Shiv Kesh Giri and Rajesh Verma.
A trial court had in March, 2007, sentenced Mittal and Agnihotri to death, but it was commuted to life by the Allahabad High Court, which said that the crime could not be classified as "rarest of rare".
Mittal had said that the court "gravely erred" in upholding his conviction on the basis of a confessional statement made by an accused to the police.
The Supreme Court today ruled on his petition.
S. Raghavendra, Mr. Manjunath's brother, told NDTV that the Supreme Court decision was expected as the case was fully argued in the High Court. "They are guilty, responsible for my brother's death and should be punished," he said.