LUCKNOW, India (AP) — Police on Wednesday began an investigation into the death of a journalist set on fire after he accused a state minister of being involved in illegal mining and land seizures in northern India.

The freelance journalist, Joginder Singh, gave a statement to a magistrate before dying Monday from burns covering 60 percent of his body. Police inspector general Satish Ganesh said Singh had implicated Uttar Pradesh state's dairy minister, Ram Murti Singh Yadav, as well as two police officers in the June 1 attack. No arrests have been made.

The minister has made no public comments or appearances since June 1.

The journalist's son, Raghvendra Singh, said it was not the first time his father was assaulted after writing an article for a local Hindi newspaper accusing the minister of involvement in illegal mining and land grabbing. The journalist later posted details of the investigative story on Facebook, after which he was visited by a group of six people including two police officers in civilian clothing.

They "barged into our house and questioned my father about the posts. They started beating him up," Raghvendra Singh said by telephone from the home in Sahajahanpur, a town about 180 kilometers (112 miles) southwest of the state capital of Lucknow. "They poured petrol over him and set him on fire."

Amnesty International demanded a thorough and impartial inquiry be conducted, and those responsible brought to justice.

"This horrific attack highlights the dangers that journalists can face in doing their jobs," said Amnesty's program director in India, Shemeer Babu.