Investigators believe the third suspect helped the father and uncle kill Hina Saleem, 21. The woman's body was found buried in the family's garden in Sarezzo on Saturday. Her father and uncle were taken into custody on Monday.

Investigators said they were looking into the theory that the grave was dug before the woman was killed. It is thought a long kitchen knife was used to slit her throat.

The Milan daily Corriere della Sera reported that the victim's father had applied for Italian citizenship two months ago. Applicants must convince authorities that they also embrace "fundamental" rights, including the right of a woman "to choose her own life", said the interior minister, Giuliano Amato.

News reports said the victim's family had been insisting on an arranged marriage with a cousin in Pakistan.