The news from the Kaliganj Assembly seat on Monday: Trinamool won the by-election and a mother lost her child.

Tamanna Khatun, 11, died when alleged Trinamool supporters hurled bombs at the homes of CPM workers during a victory march at Baro Chandghar Molangi village in the Nadia constituency.

The Class IV student was planting a sapling in the courtyard of her home when a “socket bomb” — a steel pipe filled with gunpowder and iron splinters — exploded a few feet from her.

Her mother Sabina, who had been standing beside Tamanna and was thrown to the ground by the blast, said Trinamool supporters had hurled the bomb because the family supported the CPM.

Other villagers backed her claim, adding that the homes of many pro-CPM families had been bombed.

“All those who came and killed my daughter with a bomb were supporters of Didi’s party…. They were angry because we did not vote for them,” a weeping Sabina said. “They wanted to kill my son (a CPM activist), but killed my little child instead.”

Tamanna’s father, a migrant labourer, was away.

Trinamool Congress supporters celebrate the victory in the Kaliganj by-election on Monday. Picture by Abhi Ghosh

Trinamool leaders denied their party’s involvement. Chief minister Mamata Banerjee expressed sorrow and promised “strong” action.

“I am shocked and deeply saddened at the death of a young girl in an explosion at Barochandghar in Krishnanagar police district,” Mamata said in a condolence message on X.

“My prayers and thoughts are with the family in their hour of grief. Police shall take strong and decisive legal action against the culprits at the earliest.”

Sabina said the family had no faith in the police.

Nadia police had arrested a man by late evening. Adar Ali Sheikh, the suspect, is a known Trinamool supporter, an officer in Kaliganj said.

The bombing occurred around 11am, shortly after the ninth round of counting, which left Trinamool candidate Alifa Ahmed leading by over 25,000 votes.

As local Trinamool supporters began a celebratory procession, some people entered Molangi, a known CPM stronghold, and began throwing bombs, sources said.

Sabina said around two dozen goons stormed her courtyard from various sides and let loose a fusillade of bombs.

One of the bombs exploded near where she and Tamanna stood, the impact flinging both to the ground. When the smoke cleared partly, Sabina realised her daughter was dead.

Nadia CPM secretary Meghlal Sheikh said it was not an instance of overenthusiastic celebration but a premeditated attack on political opponents.

“There was no celebration at all by the Trinamool supporters. Instead, in a planned way, they tried to unleash terror on CPM supporters but ended up killing the innocent girl. It’s horrible.”

A CPM delegation that visited the village in the afternoon said an FIR would be filed. In the evening, CPM leader Minakshi Mukherjee led a protest march to the local police outpost demanding the immediate arrest of all those involved.

A fuming Minakshi told reporters: “Trinamool goons patronised by the police facilitated the girl’s murder. The state will rise in protest.”

Nadia superintendent of police Amarnath K said: “We have begun a probe and the suspects have been identified. One has already been arrested. We suspect the incident is the fallout of local rivalry.”

Joining the CPM’s protests against the murder, the Congress demanded that the Election Commission cancel Alifa Ahmed’s victory certificate and provide ₹25 lakh as compensation to Tamanna’s family.

Alifa dismissed the allegations. “The girl’s death is very sad but this is an isolated incident. The administration should inquire whether there was a conspiracy behind it to spoil the victory celebrations,” she said.

Defeated BJP candidate Ashis Ghosh blamed Trinamool for the violence.

“The girl’s death in a bomb attack is not an isolated case, our state has become a stockyard of bombs,” he said.

“TMC goons began threatening voters as soon as the election was announced. As a result, the poll percentage dropped. Everyone said rain was the reason for the low turnout, but we know how goons terrorised voters in several areas.”

A statement from state Congress president Subhankar Sarkar said: “The EC should give him exemplary punishment…. This incident proves that the Election Commission has failed to organise terror-free elections in this state.”

Bengal’s chief electoral officer, Manoj Kumar Agarwal, has asked the Nadia district administration for a report.

Agarwal told reporters in Calcutta that the commission had no information that a victory march would take place in such a way.

“The incident is very unfortunate.... It is the district administration that gives permission for victory processions. We have sought a report,” he said.

Alifa defeated her nearest rival, Ghosh, by 50,049 votes. Congress-Left candidate Kabil Uddin Shaikh came third with 28,348 votes.