Nationalist Congress Party leader and candidate Jonathone N Sangma, his personal security officer and two party workers were killed in an explosion in Meghalaya’s Garo Hills area on Sunday, reported The Shillong Times.

The state goes to polls on February 27. Sangma, who was contesting from the Williamnagar constituency seat, had received death threats in the past.

The election in the constituency will now be deferred and the new date will be announced soon, Meghalaya’s Chief Electoral Officer Frederick Roy Kharkongor told The Hindu. He has also requested the Centre for more paramilitary forces in the Garo Hills region.

Suspected militants triggered an explosive device under the NCP leader’s vehicle in Samanda area when he was returning from an election campaign, The Shillong Times reported. The militants reportedly also opened fire at Sangma’s vehicle.

“Four bodies were found at the spot, including that of the NCP candidate,” District Magistrate Ramkumar S told NDTV.

The deputy commissioner’s office of the East Garo Hills District in a press release said preliminary investigation suggested an Improvised Explosive Device, or IED, was used in the attack. Of the four vehicles discovered at the location, Sangma’s was hit the worst, the commissioner said.

Three other people were injured and shifted to Downtown Hospital in Guwahati, the police said. The deputy commissioner’s office said no militant group had taken responsibility for the attack.

However, some unidentified people put up posters threatening Sangma at several locations in the Garo Hills. A First Information Report was filed on Friday. Sangma had been provided with two security personnel for his protection since 2011.

Meghalaya Chief Minister Mukul Sangma condoled the NCP leader’s death. “Deeply saddened to hear about the unexpected loss of Jonathone Sangma,” Mukul Sangma said on Twitter. “My heartfelt condolences to his near and dear ones. The blood of innocent spilled by the enemies of the state will not disturb peace in Meghalaya.”

The chief minister said the perpetrators of the crime will be “apprehended expeditiously and brought to book”. “This desperate act will not be tolerated,” he added.