On December 27, 1988, Sidhu and his aide Rupinder Singh Sandhu were in a Gypsy parked in the middle of a road near the Sheranwala Gate crossing in Patiala, when the victim and two others were on their way to a bank to withdraw money, according to the prosecution.

According to the news agency, when they arrived at the crossing, Gurnam Singh, driving a Maruti car, discovered the Gypsy in the middle of the road and urged the passengers, Sidhu and Sandhu, to remove it.

According to the prosecution, this resulted in heated arguments, during which Gurnam was battered and taken to the hospital, where he was pronounced dead.

A trial court cleared Sidhu of murder charges in September 1999.

In December 2006, Punjab and Haryana High Court overturned the decision, finding Sidhu and Sandhu guilty of culpable homicide not amounting to murder under Section 304 (II) of the Indian Penal Code.

They were convicted to three years in prison and fined Rs one lakh apiece by the High Court.

On May 15, 2018, the Supreme Court overturned the High Court order but found Sidhu guilty of injuring a senior citizen.