Punjab Police chief V K Bhawra on Monday said he never called Sidhu Moosewala a gangster or that he was affiliated with gangsters.

The director-general of police's (DGP) clarification came after the slain Punjabi singer's father Balkaur Singh wrote to Chief Minister Bhagwant Mann demanding a public apology from Bhawra for linking his son's killing with a gang war.

In the letter to the chief minister, Singh had also demanded a probe by a sitting high court judge into the killing of his son.

Later, in a statement, DGP Bhawra said he has the highest respect for Sidhu Moosewala, and called him a celebrated artist and a cultural icon of Punjab.

Condemning the killing, the state police chief said an investigation was underway and the perpetrators of the crime would be brought to justice.

Bhawra further said on no occasion, has he ever said that Moosewala was a gangster or affiliated with gangsters.

"Claims and counterclaims by various persons claiming to be gangsters are being made on social media. One Goldy Brar has claimed responsibility on behalf of the Lawrence Bishnoi gang (for the killing of Moosewala)," said the DGP.

The investigation would look into all aspects, he further said.

The DGP stated that he has been misquoted by a section of the media and he has the highest regard for Moosewala.

Moosewala, 28, was shot dead on Sunday by unidentified assailants in Punjab's Mansa district, a day after the state government curtailed his security cover. His cousin and a friend, who were travelling in a Mahindra Thar jeep with him, were also injured in the attack.

He had fought the recent assembly election in Punjab on a Congress ticket from Mansa and was defeated by the AAP's Vijay Singla.

The Punjab police DGP on Sunday said, "This incident (killing of Moosewala) seems to be a case of an inter-gang rivalry." He added that the Lawrence Bishnoi gang was behind the killing.

At least three weapons and 30 empty cartridge cases were recovered from the killing site.

Shubhdeep Singh Sidhu, known as Sidhu Moosewala, was among the 424 people whose security was withdrawn or curtailed by the Punjab Police on Saturday temporarily.

Moosewala was left with two Punjab Police commandos after the state police withdrew two of four commandos from his security cover. However, he neither took the remaining two commandos nor his bullet-proof vehicle with him on Sunday.