NEW DELHI, May 14: The Indian government must set up an impartial probe into at least 31 killings by police in western Gujarat state, rights group Amnesty International said on Monday.

The Gujarat government has come under fire since admitting in the Supreme Court last month that a Muslim man was killed by police in a staged gunbattle.

It has emerged that the man's wife was also killed, apparently as part of a bid to destroy evidence in the case.

Amnesty said it believed at least 31 people -- including “so-called terrorist suspects” -- had been unlawfully killed by police in Gujarat since 2002.

“Investigations are a critical factor in the prevention of further unlawful killings,” the rights body said in a statement.

The demand came as Gujarat's government told the Supreme Court that one of the six police officials arrested over Sheikh's murder had confessed to the crime.

Sohrabuddin Sheikh was shot dead and then accused of plotting to kill Gujarat Chief Minister Narendra Modi, who has been blamed for sectarian riots which left at least 1,000 people dead, mostly Muslims, in the state in 2002.

The Supreme Court is hearing a petition by Sheikh's brother to transfer the murder probe to federal investigators.

The case has sparked demands in several other Indian states for fresh probe into similar killings by police, army and paramilitary forces, some carried out several decades ago.—AFP