An autopsy has confirmed that Nido Tania died from injuries he suffered in an alleged racist attack, local media reported on Monday.
Nido Tania, 20, a native of remote Arunachal Pradesh state, died in the Indian capital on January 30, hours after he was beaten by a group of men in south Delhi.
His death triggered a national debate on widespread discrimination against Indians from the north-eastern region, as well as students from Africa who have been attacked.
The post-mortem report that was to be submitted by the Delhi police in a court on Monday, said Tania died as a result of injuries to his head and face, broadcaster CNN-IBN reported.
Three suspects under arrest would now be charged with murder, NDTV network said.
Delhi police spokesmen were not available for comment.
Legislators and activists have condemned the killing and called for measures to combat racial discrimination.
There are an estimated 200,000 people from the north-eastern states studying and working in the capital. Natives of those states have ethnic features closer to China and Myanmar than to northern India.
Several assaults on young women from the north-east have been reported in New Delhi in recent years.