A 30-year-old man was arrested on Thursday on the charge of killing inspector Subodh Kumar Singh during the December 3 mob violence in Bulandshahr that followed the discovery of cow carcasses in a village.

Officers alleged that Prashant Nat, a driver based in Delhi, had snatched the officer’s service revolver and shot him.

“We will be able to give more details after interrogation,” senior superintendent of police Prabhakar Chaudhary told The Telegraph.

Police sources said Nat was visiting his home in Chingrawathi village, where his wife, two kids and parents live, when the violence erupted and caused the death of Singh and a student, Sumit Kumar. Nat had not been named in the FIR.

The police had on December 8 arrested an army jawan, Jitendra Malik aka Jeetu Fauji, from Jammu and Kashmir and alleged he was the killer. They backtracked two days later.

Officers have said they have stopped searching for the prime accused, district Bajrang Dal convener Yogesh Raj, and his Sangh parivar colleagues Upendra Raghav and Shikhar Agrawal and are “waiting” for them to “surrender”. Opposition parties have accused the BJP government of trying to protect them.

Additional director-general Anand Kumar had said on Wednesday that Nat had been identified as the killer from video footage and eyewitness statements. He had added that Yogesh had mobilised the mob, incited them to violence and argued with the slain officer.

Of the 27 named in the murder and rioting FIR – apart from 60 unknown people --- 21 have been arrested. Seven others have been arrested on cow slaughter charges.