Dhankar and his four friends were allegedly assaulted by Kumar and others at the stadium on the intervening night of May 4 and 5 over a property dispute.
There were "murmurs" that Kumar was scared of the two tenants living in a house he owned and he "nursed a deep grudge" about the loss of respect in the eyes of his students.
The final report, which named Kumar as the main accused, has been filed before Chief Metropolitan Magistrate (CMM) Satvir Singh Lamba.
Sushil Kumar Modi said that no passenger fatality was reported in the last two years because of enhanced safety measures throughout the country.
During the interrogation, Grewal disclosed that Sushil first scolded and beat up Vikas, Arvind Brahamchari and Ravinder aka Bhinda at Chhatrasal Stadium.
Sushil Kumar was arrested along with co-accused Ajay Kumar on May 23 from outer Delhi's Mundka area in connection with the Chhatrasal Stadium brawl.
According to the counsel of the accused, he has been shifted to Tihar jail number 2 from Mandoli jail, where he was earlier lodged.
The police produced Anirudh before Metropolitan Magistrate and sought his custody for seven days. The court, however, allowed his police interrogation for only four days.
The international wrestler is facing charges of murder, cupable homicide and kidnapping.
The judge further said it is apparent that basic needs and necessities of the accused are being taken care of in the jail as per the provisions of Delhi Prisons Rule, 2018.
Sushil, who is facing charges of murder, cupable homicide and kidnapping, is currently lodged in Delhi's Mandoli Jail.
Sushil Kumar, who was produced before Metropolitan Magistrate Rashmi Gupta at the end of the four-day police custody, was sent to judicial custody for 14 days.
Meanwhile, the crime branch of Delhi Police took the Olympic gold medallist, Sushil Kumar, to Haridwar to investigate his hideouts and the people who helped him while he was absconding.
While sources said that Sushil Kumar repeatedly told the police that he did not intend to kill the victim, investigation has so far revealed that 13 people were involved
Sushil Kumar and his associates allegedly assaulted wrestler Sagar Dhankar and two of his friends Sonu and Amit Kumar on the intervening night of May 4 and 5.