The 26-year-old hanged himself on 18 January last year, days after he and four other students were suspended by the Hyderabad Central University and barred from its hostel. His friends and family alleged that he was ostracized because he was a Dalit.
A former judge, Justice AK Roopanwal, has concluded in his report that Mr Vemula was not a Dalit and he committed suicide because he was frustrated due to personal reasons not related to his eviction from the hostel.
In the report made public on Tuesday, the former Allahabad high court judge says Mr Vemula was a "troubled individual" and unhappy over several reasons.
"His suicide note is on the record which shows that Rohith Vemula had his own problems and was not happy with worldly affairs," the report says. "He was frustrated for the reasons best known to him...He also wrote that he was all alone from childhood and was an unappreciated man. This also indicates his frustration. He did not blame anybody for his suicide."
The report also absolves union ministers Bandaru Dattatreya and Smriti Irani of any role; Mr Vemula's friends had accused them of pressuring the university to punish the five scholars.
"If he would have been angry with the decision of the university, certainly either he would have written in specific words or would have indicated in this regard. But he did not do the same. It shows that the circumstances prevailing in the university at that time were not the reasons for committing the suicide," the retired judge says.
Whether Mr Vemula was a Dalit or not added a new layer to the suicide controversy, with some alleging that he had lied about his caste and student protests against discrimination were baseless.
The cases registered against the university vice-chancellor and the union ministers were under the Prevention of Atrocities Against SC/ST Act.