Serial rapist John Xydias is faced with the possibility of additional charges involving an underage victim.

On Tuesday he appeared in Melbourne’s Magistrate Court where the police asked for permission to interview him.

Mr Xydias did not challenge the request and subsequently was questioned by police for an hour.

Allegedly the police are investigating if Mr Xydias sexually penetrated a girl under the age of 16 as well as committing an indecent act with a girl under the age of 16.

He has already pleaded guilty to 86 charges of rape and sexual assault on 11 women between 1991 and 2006.

It was found that he would first drug his victims while he even filmed some of the attacks.

The police recovered 17 such tapes.

He is currently awaiting sentencing.