Salman Khan during a film award ceremony. File

Brar, who is currently said to be aboard, is reportedly facing two dozen criminal cases lodged against him in several Indian states.

"Brar is a resident of Rajasthan's Hanumangarh but presently he is living abroad. He is a known gangster of Rajasthan. He was having good rapport with Anmol, the brother of gangster Anandpal, who was killed in an encounter," the police source said.

The Mumbai police had also suspected the possible involvement of the Bishnoi gang, and as a precaution, beefed up security at the Khans' residence in Galaxy Apartments, Bandra West, since last Sunday.

Joint Commissioner of Police Vishwas Nangre-Patil had also met Home Minister Dilip Walse-Patil to brief him.

Mumbai police had suspicion that the potential attackers may have conducted a discreet recce of the Khans' local movements and their residence.

Bishnoi had earlier vowed to kill Salman Khan after the actor was accused in the black buck poaching case of 1998 in Rajasthan.

Salim Khan, 87, was handed over an unsigned, hand-written threat letter by an unknown person on a bench where he normally rests after jogging at the Bandra Bandstand promenade, around 7:30am on Sunday.

It was addressed to him and his son Salman and facing something amiss, they immediately alerted their security to inform the police.

Taking serious cognisance, the Bandra police had lodged an FIR against unknown persons for issuing the death threats and launched their probe. The Mumbai Police Crime Branch had also started its own investigations.

The threat letter ended with a couple of initials including 'L.B.' which the police suspected refers to 'Lawrence Bishnoi.’

Indo-Asian News Service