There doesn’t appear to be any doubt.
//The prosecution presented evidence including witness statements, the victim's statement, fingerprints, DNA testing, and dental modelling//
http://en.wikipedia.org/wiki/2012_Delhi_gang_rape_case
Interesting to note the defence lawyer’s statement to the media.
//their lawyer, Manohar Lal Sharma, said in a media interview that the victims are responsible for the assault because they should not have been using public transportation and, as an unmarried couple, they should not have been on the streets at night. He went on to say: "Until today I have not seen a single incident or example of rape with a respected lady. Even an underworld don would not like to touch a girl with respect."[92] He also called the male victim "wholly responsible" for the incident because he "failed in his duty to protect the woman".//
Isn’t that disgraceful?