Can I file FIR on behalf of someone else

my college mate was touched by a stranger without her consent .i gave complaint to police.but she is not ready to give statement to police .when police called her she doesn't deny it ,but she is telling that she doesn't want to get in to case .so whether police have to take FIR on my petition? what should i do if local police doesn't take the FIR on my complaint saying that we dont have her statement?