Nandi said security guards at NIS stopped him from entering the premises, saying they they had orders from senior Sports Authority of India (SAI) officials to bar his entry.
“I was pushed and one person held my hand. They said that there were orders against my entry into the NIS premises. When I asked where the written orders were, they assaulted me,” Nandi told reporters outside the NIS gates.
Nandi said he wanted to meet Mudgal, who has been appointed by the sports ministry to probe the systemic doping by athletes at NIS Patiala in recent years.
Eight Indian athletes had recently tested positive for taking banned performance enhancing drugs.
Quarter-milers Ashwini Akkunji, Mandeep Kaur, Sini Jose, Juana Murmu, Priyanka Pawar and Tiana Mary Thomas, shot-putter Sonia and men's long-jumper Hari Krishnan Muralidharan have tested positive in dope tests conducted either out of competition or during an inter-state meet.
Ashiwini, Mandeep and Sini were members of the famed women's 4×400 metres relay team that won the gold medal in last year's Commonwealth Games and the Asian Games. Ashiwini also won the gold in the 400 metres hurdles at the Asian Games.
The doping scandal has led to sacking of Ukranian coach Yuri Ogorobonik, who trained the six women athletes who have tested positive for banned substances.
Sports Minister Ajay Maken said Monday that the government was planning to table a new law in the monsoon session of the parliament (beginning August 1) to curb the doping menace.