Bangalore, Nov. 2: An associate of Chhota Shakeel facing a slew of cases that included a plot to kill L.K. Advani was hacked to death today along with a co-accused inside a Mangalore prison by suspected members of a rival gang.

Madoor Isubu - a long-time associate of Shakeel who is in detention in Indonesia and could be brought to India soon - was killed along with an accomplice, Ganesh Shetty, at breakfast time in Mangalore District Prison.

Isubu too had been deported to India in 2010 from Riyadh, where he had fled after jumping bail in a riot case.

Both Isubu and Ganesh were in their early forties and hailed from Mangalore, said police commissioner S. Murugan. The officer didn't identify the rival gang but police sources said they were linked to another underworld operative, Vicky Shetty.

The sources said the attack - dubbed the biggest in a Mangalore jail - was "most likely" in retaliation to Isubu's alleged threats to a Vicky aide in the prison.

The police ruled out any communal angle. "Ganesh (a Hindu) was also part of Isubu's gang," Murugan said, referring to the prison clash in the communally sensitive coastal district.

Isubu and Ganesh were killed with "sharp-edged weapons". "The weapons were possibly thrown in from outside the periphery wall," Murugan said.

Two guards and the jail superintendent suffered injuries when they tried to intervene in the fight, as did 10 inmates belonging to the two gangs, which had reportedly clashed repeatedly in the past three days.

In his heyday, Isubu had allegedly played a key role in establishing links between the underworld and Maoists in south Karnataka.

He was accused of plotting Advani's murder during a trip by the BJP veteran to Udupi, near Mangalore, in 2010 - just days before he was detained in the Saudi capital ahead of his deportation.

Among his 20-odd criminal cases - the trial is under way in all of them - are four for murder, including one for killing a local BJP leader, Sukhananda Shetty, in 2006.

Before that, he was arrested for allegedly inciting riots in Ullal, near Mangalore, in 2001. He got bail in 2003 but fled soon after and was located seven years later in Riyadh#.