Radhakrishnan told reporters that a five-member team has already submitted the post-mortem report of Muthukrishnan, based on which a judicial probe will be initiated.
Muthukrishnan had allegedly committed suicide at a friend's house in New Delhi on March 13.
As Radhakrishnan was addressing the media, some students and activists started raising slogans against the BJP-led Central government.
In the melee, a man allegedly hurled a chappal and a stone at the Union minister, which, however, missed the target.
More From This Section
Radhakrishnan described the incident as "undesirable" and asked the Tamil Nadu BJP unit not to make a big issue of it.
In response to a question on Muthukrishnan's alleged suicide, he said, "I will not accept (accusations) that this (death) has happened because of the BJP coming to power."
These incidents "have been happening at many places for the last 60 years", he claimed.
The Union Minister of State for Road Transport and Highways and Shipping said in Muthukrishnan's death, he felt like having lost "my own younger brother".
Earlier, Radhakrishnan placed a wreath on the body of Muthukrishnan, while Salem Collector Sampath paid floral tributes and handed over a cheque of Rs 3 lakh announced by the state government to Jeevanandam, father of Muthukrishnan.
The M.Phil student, who was staying at the Jawaharlal Nehru University's Jhelum hostel in New Delhi, was found hanging from the ceiling fan at a friend's residence in south Delhi's Munirka area on March 13.
In a series of tweets, Radhakrishnan said his party will continue to voice support for the welfare of Tamil Nadu and the students of the state.
Meanwhile, state BJP chief Tamilisai Soundararajan flayed the chappal-throwing incident.