The main accused in the rocket propelled grenade attack at the Punjab Police headquarters in Mohali was apprehended from Mumbai on Thursday, DGP Gaurav Yadav said.

Charat Singh was apprehended by the state police in a joint operation with central agencies and the ATS, Maharashtra.

He is a key operative and associate of Canada-based terrorist Lakhbir Singh, alias Landa, the DGP tweeted stressing that the Punjab Police will "strive to make the state crime-free as per vision of CM Bhagwant Mann".

The state police had earlier said Landa played a key role in the terror attack on May 9. No one was injured in the incident.

According to a Punjab Police statement later, Yadav said Charat Singh had built a crime network across the state with the help of Landa. He was providing logistic support and shelter to the foot soldiers who carried out the rocket-propelled grenade (RPG) attack, he added.

Charat Singh had also procured the RPG, AK-47 and other weapons from across the border with the active support of Pakistan's ISI through Pakistan-based terrorist Harwinder Singh, alias Rinda.

Meanwhile, Punjab Police Inspector General of Police Sukhchain Singh Gill said they have so far apprehended nine people, including a juvenile, in this case.

Gill said Police teams are on a hunt to arrest the last accused, identified as Deepak Kumar of Haryana's Jhajjar. He had carried out the RPG attack.

The IGP said Charat Singh is a habitual offender and has been facing several cases of heinous crimes, including murder and attempt to murder.

He was serving a life sentence in a murder case and at the time of the RPG attack was out on parole, he said.

"During his parole period, Charat Singh reassembled his associates, including Nishan Kulla, from the Tarn Taran area to carry out the RPG attack, which was aimed at destabilising communal harmony and peace in the state," said the IGP.

The Delhi Police had last week apprehended two terror accused, including a juvenile, in connection with the RPG attack.

The juvenile was also tasked with "eliminating" actor Salman Khan, police had said.

Apart from the juvenile, a special cell of the Delhi Police had arrested Arshdeep Singh in connection with the recovery of an improvised explosive device (IED) in Haryana on August 4, the Delhi Police had said.

According to police, the Lawrence Bishnoi and Jaggu Bhagwanpuria syndicate tasked the juvenile, Deepak Surakpur and Monu Dagar with "eliminating" Khan.