The 11-year-old girl whose body was found in Baruipur near Kolkata was sexually assaulted and thrown into the water alive, the post-mortem report indicated as Bengal chief minister Suvendu Adhikari on Monday said his government will ensure the child’s family gets justice and will also make those who instigated violence in the area “suffer beyond their imagination”.

The girl went missing on Saturday after she left her home in South 24 Parganas' Baruipur, around 25 km from Kolkata, to buy a birthday gift for a friend. Her family had lodged a missing complaint with the police. The body was recovered on Sunday.

After the body was found, a mob lynched a man suspecting his involvement in the girl's rape and murder.

A senior police officer on Monday said preliminary findings in the post-mortem revealed injury marks in the girl's private parts, besides scratch and bite marks on her body.

It also indicated that the girl's head had either been struck with a heavy object or banged against a hard surface, the officer said, citing the post-mortem report.

The report suggested that the child was alive when she was thrown into the pond. Water was found in her lungs and stomach during the examination.

The findings further suggested that excessive bleeding from the head injury, along with drowning, led to her death, police sources said.

Police arrested the key accused in the case on Monday, taking the total number of arrests in the case to three.

"The investigation is at a crucial stage. We are examining all evidence. The preliminary post-mortem findings are being corroborated with other material collected during the probe," a senior police officer said.

Police examined CCTV footage from the area, which purportedly showed the girl being taken away by four persons, he said, adding they were analysing the footage to establish the identities of the accused and their role in the crime.

"We are pursuing all available leads. CCTV footage, forensic evidence and witness statements are being examined. Those involved will be identified and arrested at the earliest," the officer said.

CM vows death and suffering

"It's a crime of unspeakable horror,” Bengal chief minister Adhikari said in Kolkata on Monday. “I have spoken to the parents of the victim and the government is doing everything that the family has asked for. They will get justice and the criminals will get capital punishment. I am happy that the family has reposed its trust in the government.”

Besides the main crime, three cases have also been lodged in connection with the violence that followed, he said.

"There was an incident of mob lynching with a communal angle to it. Railway tracks were damaged, bringing back memories of the 2019 anti-CAA protests and the more recent anti-Waqf Act protest. These apart, two CRPF jawans were assaulted, and a police vehicle was torched," the chief minister said.

"We will surely provide justice to the family. But we will also make those frustrated souls, who locked themselves up in their rooms after getting defeated in the elections and who orchestrated the violence, suffer beyond their imagination," he warned.

It was seen as a reference to local Trinamool leaders suspected of taking part in Sunday's unrest.

Mamata’s Trinamool leaders visit

A team of Trinamool leaders loyal to Mamata Banerjee reached Baruipur on Monday amid prohibitory orders and met the family of the victim.

They held a meeting at Banerjee's residence in south Kolkata before leaving for Baruipur. On Sunday night, the TMC alleged that barricades were erected and there was heavy police deployment outside the former chief minister's residence to prevent her from visiting the victim's family.

The team included former assembly speaker and local MLA Biman Banerjee, Rajya Sabha MP Dola Sen and Joynagar MP Pratima Mondal, among others.

Baruipur remained tense on Monday, a day after locals held a protest demanding the arrest of the accused. The demonstration had escalated to brick batting, during which a major road was blocked, tyres burnt and police vehicles were vandalised.

Police have clamped prohibitory orders under Section 163 of the BNSS in Baruipur and its adjacent Narendrapur and Sonarpur police station areas in the aftermath of Sunday's violence and deployed heavy security.

The state government has constituted a six-member Special Investigation Team (SIT), headed by the local additional superintendent of police, to probe the crime.

"Police should have been proactive in tracing the criminals. The locals had no choice but to resort to protests and it was spontaneous," said TMC's Baruipur Dakshin MLA Biman Banerjee.

"It was unfortunate that Mamata Banerjee was stopped from visiting the victim's family," he said and termed it an attempt to throttle people's voice.