Islamabad, Nov 16 (IANS): Two men killed their 15-year-old sister and cousin on Friday in Shangla district of Pakistan's Khyber Pakhtunkhwa province in a suspected case of honour killing, the police said.

A police official told Dawn online that the girl's brothers suspected the two were involved in a relationship and killed them in the name of "honour". The crime took place in the Laray area of Martung district in Shangla.

The police official said that the deceased were first cousins. The girl was unmarried while the 27-year-old man, Said Muhammad, had four children.

The murdered man's father, Khan Said, told the police that his two nephews shot his son dead while he was working in the fields. They then went back home and killed their teenage sister.

The suspects then fled the crime scene.

Khan Said said he had registered a first information report in the Martung police station. An investigation into the case was underway.