Bhubaneswar, Sep 12 (IANS): Authorities in Odisha Friday ordered a probe into the killings of four of a family, including two minor children, in Nayagarh district Sep 6.

The order came a day after one more person was killed and 19 others, including 15 policemen, were injured when over 3,000 angry villagers clashed with policemen over their failure to arrest the Sep 6 killers of the four.

"The crime branch of Odisha Police has been told to investigate the murder," Director General of Police Sanjeev Marik told IANS.

The four were found murdered in their home in the district's Chandpur area Saturday night.

Sarat Patra, who works in a private firm here, found his father, his wife and two children - five and nine years old - lying in pools of blood at his home when he reached there Saturday night.

Although the reason behind the gruesome murders was not yet clear, police have said the two children were asphyxiated with a pillow, while the two adults were killed with sharp-edged weapons.

The district headquarters of Nayagarh is about 90 km from here.

Marik said Ranpur police station chief Chandrasekhar Mohanty was placed under suspension for negligence.

Hundreds of policemen were deployed in the area to maintain law and order.