The singer's death was an organised and brazen killing, Special Commissioner of Police, Special Cell, HS Dhaliwal, told the media.
Six out of the eight shooters, whose pictures were sent out, have been identified, he added during the media briefing.
Out of the shooters, the role of four has been established in the murder.
Delhi Police Special CP (Special Cell) HS Dhaliwal, on Wednesday, 8 June called Lawrence Bishnoi the mastermind behind Moose Wala's murder, adding that a close associate of one of the shooters had been arrested.
Siddhesh Hiraman Kamle alias Mahakal, who was a close associate of the main shooter, was arrested earlier this week from Pune in a joint operation with the Maharashtra Police, in a case under the Maharashtra Control of Organised Crime Act.
The Punjab Police, on 7 June, arrested at least eight people for aiding Moose Wala's shooters with logistical support and recce, and for harbouring them.
Punjabi singer-politician Sidhu Moose Wala was fatally shot on 29 May by unidentified men near Jawaharke village in Punjab's Mansa district. According to the reports, the autopsy suggested that the body received 25 bullet injuries.
(With inputs from PTI.)