The special investigation team (SIT) on Monday arrested Inspector General Paramraj Singh Umranangal, who was commanding the police force when they allegedly opened fire on people protesting against desecration of religious texts in Punjab in 2015, citing "sufficient evidence" against him.
Two people were killed in police firing in Behbal Kalan and Kotkapura areas in Faridkot district in October 2015.
The Special Investigation Team, set up to probe the incidents, last month arrested former Moga district SSP Charanjit Singh Sharma, the first person held after the SIT was formed last year. He was leading a police team that allegedly opened fire at protesters in Behbal Kalan.
"I can confirm that Paramraj Singh Umranangal has been arrested from Chandigarh on the basis of sufficient evidence we have against him," SIT member Kunwar Vijay Pratap Singh said.
"We have questioned a number of people, including police officials, as part of our investigation. He was questioned twice. We have got sufficient evidence that...the procedure adopted (to open fire) was not correct," Mr Singh said.
"It was proved that protesters were sitting peacefully and there was no provocation by them. It was also proved that firing was opened deliberately," he said.
The SIT member said Mr Umranangal was posted as Ludhiana Police Commissioner when the incident happened.
"During investigation, it came to light that he was commanding everything and force in strength had gone there (the spot where protesters were sitting) from Ludhiana. He was managing everything," said the official.
Asked who ordered the firing, Mr Singh replied, "As the investigation will progress, more things will come to light. For now, it is sufficient to say we have enough evidence, sufficient base for arresting him".
Mr Umranangal will be produced before a court in Faridkot on Tuesday, he said.
Replying to another question, the official said the SIT will question more people if required. "It is a transparent investigation, and things are being made available in public domain."
Mr Umranangal was previously questioned by the SIT last November.
Punjab government last year added the names of a few police officials, including former SSP Sharma, in an FIR registered in connection with the firing incident at Behbal Kalan.
The names were added on the recommendation of the Ranjit Singh Commission report.