Inspector Subodh Kumar Singh's family described him as an upright police officer.

Highlights Police said they will determine age of carcasses to check for foul play

A cop was among two was killed on Monday in a clash over cow carcasses

The main accused -- Bajrang Dal member Yogesh Raj -- is still at large

Uttar Pradesh police are investigating if a protest over the alleged slaughter of cows was staged to spark tension during a Muslim religious event in Bulandshahr on Monday, news agency Reuters has reported. A police officer was among two people killed in the incident.

Four of the 27 accused in the incident, which occurred ahead of the 2019 Lok Sabha elections, have been arrested. However, the main accused -- Bajrang Dal member Yogesh Raj -- is still on the run.

Reuters quoted Uttar Pradesh Additional Director General (Law and Order) Anand Kumar as saying that they will try and determine the age of the bovine carcasses to check if there was any foul play involved. "If there is anything like that, the details will come out. An intelligence investigation is being taken up, and all these aspects will be looked into," Mr Kumar said at a news conference, adding that the religious event has ended peacefully.

Inspector Subodh Kumar Singh was allegedly killed after a mob surrounded his team in Bulandshahr over the recovery of five carcasses in a nearby forest. The mob left nearly six policemen wounded, burned down a police station and set several vehicles on fire.

The killing of Inspector Subodh Kumar Singh has created a major controversy in the state, with his family members describing him as an upright police officer who investigated every case unmindful of political pressure. "He was a very good human being. He lost his life in the line of duty," said his elder son, Shreya. "He would sometimes be told not to investigate some case... but he always did."

The Yogi Adityanath government's offer of Rs 40-lakh compensation for Mr Singh's family, Rs 10 lakh for his parents and a government job for a relative has failed to placate the family. "Subodh was murdered because he was investigating the mob killing of Mohammad Akhlaq at Dadri in 2015; it's a conspiracy. We do not want money... the chief minister only keeps saying cow-cow-cow," news agency ANI quoted the police officer's sister as saying.

The dead police officer was probing the Akhlaq mob killing, but was transferred before he could complete the investigation. Anand Kumar refused to disclose the reason for Mr Singh's transfer.

Bhola Singh, the BJP lawmaker from the district, told reporters that protests had escalated after two recent incidents of cow slaughter.

(With inputs from Reuters)