'Serial killer' Mallika has reportedly confessed to her role in six murders but denied any knowledge about any cases of disappearances, said a senior police official in Bangalore on Friday.

Mallika alias Kempamma has refused to accept the allegations that she had killed more women, other than the six murders in which she had admitted her complicity, said the official, who is involved in the investigations.

After her arrest on December 30, four cases of missing women have been registered by the police, following complaints from relatives suspecting Mallika's involvement in the disappearances.

Bangalore district police have been asked to file an application before a jurisdictional magistrate, seeking permission to subject the 43-year-old Mallika to a narco-analysis test in the wake of her non-cooperation in revealing information about her criminal acts, the official said.

Mallika would be subjected to the test as soon as the court gives its permission, he added.

Mallika, who is currently in police custody, was arrested on December 30 by the Bangalore police.