STOCKHOLM: A Swedish police officer involved in the investigation against Julian Assange over sexual assault charges knew one of the two plaintiffs in the case against the WikiLeaks founder, police have confirmed.

The admission comes after a newspaper reported that an unnamed female officer in charge of questioning the two alleged victims, who have accused Mr Assange of rape and molestation, had internet contact with one of them more than a year before the accusations surfaced last August.

Mr Assange's Swedish defence lawyer, Bjoern Hurtig, has said the revelation raises very serious concerns and described the officer's role in the investigation as ''highly inappropriate''.

The policewoman became friends with the woman referred to in court as Miss A through Sweden's Social Democratic party, the daily paper Expressen reported.

Mr Hurtig added that if it was proven that Mr Assange's first interrogation was not objective, ''then there was really no grounds for the investigation to begin with, and perhaps the whole probe needs to start over''.