Gunmen on motorbikes ambushed and killed Chandranath Rath, a close aide to senior BJP leader Suvendu Adhikari, in West Bengal’s Madhyamgram area late on Wednesday.

The killing came roughly 48 hours after Prime Minister Narendra Modi’s Bharatiya Janata Party swept state elections, winning 207 of 294 assembly seats in its first-ever victory in the eastern state. Police said the attackers used fake registration plates and remain at large.

What happened in the West Bengal BJP aide killing?

Eight gunmen on four motorcycles followed Rath’s vehicle and used a smaller car to block the road before opening fire at close range.

Rath, 41, sustained multiple gunshot wounds to the chest and abdomen and was declared dead on arrival at hospital. His driver, Buddhadeb Bera, also sustained serious injuries in the attack.

Who was Chandranath Rath?

Rath was a former Indian Air Force serviceman who became one of Adhikari’s most trusted aides, playing a key role in election management particularly in Nandigram.

Adhikari, the leader of the opposition who is now tipped to become West Bengal’s chief minister, described the killing as a “pre-planned, cold-blooded murder.” He alleged that the assailants had conducted reconnaissance for three to four days before the attack.

West Bengal police chief Siddh Nath Gupta told AFP the shooting occurred at around 11pm on Wednesday, and that the motorbikes used to stop Rath’s car had been seized. He confirmed the bikes carried fake registration numbers and that a search for the assailants was underway. Police have also begun examining CCTV footage from the area.

How much post-poll violence has there been in West Bengal?

Rath’s killing brought the total number of people killed since Monday’s election results to at least five. The BJP and the All India Trinamool Congress have traded accusations over the deaths since the results were announced.

BJP West Bengal president Samik Bhattacharya called Rath’s death “a planned murder” and alleged that the TMC was responsible.

The TMC rejected any involvement in the shooting but accused the BJP of targeting its own supporters. “We strongly condemn the brutal murder of Chandranath Rath,” the party said in a statement, adding that it also condemned attacks on TMC members “allegedly carried out by BJP-backed miscreants.” Neither party has produced evidence to support their respective allegations.

What is the political significance of BJP’s West Bengal win?

Analysts say the BJP’s victory in the largely Bengali-speaking state is one of its most significant since Modi was first elected prime minister in 2014. The win expands the party’s dominance beyond the Hindi-speaking heartland of north and central India. West Bengal had been governed by Modi’s fierce critic Mamata Banerjee, leader of the TMC, since 2011.

Banerjee lost her own seat in the polls and has rejected the results. The BJP said it will swear in its new chief minister on Saturday.