In February, he defected from the Congress, India’s main opposition party, to join the unaffiliated regional National Congress Party (NCP), which is part of the ruling BJP coalition.
Maharashtra Deputy Chief Minister Ajit Pawar, from the same party as Siddiqui, said he was shocked by the “cowardly attack”.
Siddiqui was known for lavish parties and close association with Bollywood superstars.
The shooting took place amid heightened security because of a major Hindu festival in the city.
Opposition parties have criticized the government, claiming serious security deficiencies. The state government has promised a thorough investigation.
Although two suspects were taken into custody, the motive is unknown. Police are looking for a third suspect.
Some Indian media reported that the suspects said they were part of a gang run by notorious criminal Lawrence Bishnoi.
Bishnoi is currently serving a prison term for his involvement in several high-profile murder cases, including murder Indian rapper Sidhu Moose Vala in 2022.
The shooting comes weeks after Siddiqui’s security was beefed up following death threats.
