The cause of death of two teenage Dalit girls in Uttar Pradesh’s Unnao district could not be ascertained from their postmortem conducted on Thursday, PTI reported, citing Uttar Pradesh Director General of Police Hitesh Chandra Awasthi. The two girls were found dead in a field on Wednesday, in what the police initially said was a suspected case of poisoning.

Another 17-year-old girl, who was also found at the same spot, was being treated in a Kanpur hospital. A medical bulletin said her condition was critical but stable, adding that it was also a suspected poisoning case.

“The postmortem of the two girls was done by a panel of doctors and no injury before death or external injuries were found on their bodies,” Awasthi said on Thursday. “The cause of death could not be ascertained and viscera has been preserved for chemical analysis. We are taking help of forensic experts and looking into all possibilities.”

The incident occurred in Babuhara village under Asoha police station in Unnao district, according to PTI. The girls had gone to get fodder for their cattle. Their family members found them lying in their field in an unconscious state after they did not return by evening, the police said. Doctors declared the two girls dead on arrival at a nearby hospital.

The Uttar Pradesh Police chief said six police teams have been constituted and senior officials are supervising the investigation.

The police have registered a first information report against unidentified persons under Sections 302 (Punishment for murder) and 201 (Causing disappearance of evidence of offence or giving false information to screen offender) of the Indian Penal Code, The Hindu reported.

The girls’ brother alleged that they were found with their hands and feet tied up. “We found them tied up with clothes like their chunni [scarf],” the brother said. He also told India Today that the family did not suspect anyone in particular. “We did not have any enmity with anyone,” he said. “We don’t have suspicion on anyone.”

The police, however, said that they prima facie did not find any injury marks on the girls or signs of struggle at the site where they were found. Inspector General (Lucknow Range) Laxmi Singh told The Indian Express that they were yet to confirm if the girls were tied up. “The brother has given a statement saying this, but we can’t say anything because the bodies were removed before the police reached the spot,” Singh said.

Kulkarni added that there was a contradiction in the statements of the victims’ mother and brother. “The girls’ brother had said their hands and feet were tied, while her mother said that the scarf was around their neck,” he said, according to PTI.

Meanwhile, on Thursday, a group in Unnao gathered to oppose the burial of the minors, and protested against the alleged detention of four family members of the victims, reported the Hindustan Times. They also called for a Central Bureau of Investigation inquiry into the girls’ deaths.

However, the police denied reports of detention. “There is no such attempt,” Purwa Circle Officer Ramesh Chandra Prayalankar told The Hindu. “They [the family members] were called to understand the sequence of events and now they have been sent home under police protection to conduct the last rites. As it had turned dark, the family wanted to conduct the last rites on Friday.”

The Opposition demanded a high-level inquiry into the incident, while Chief Minister Adityanath sought a detailed report from the police chief.

Congress leader Rahul Gandhi hit out at the BJP government in Uttar Pradesh. “The UP government is not only crushing Dalit society, but also the honour and human rights of women,” he tweeted. “But they should remember that I and the entire Congress party will stand as the voice of victims and will endeavour to get them justice.”

Meanwhile, Congress General Secretary Priyanka Gandhi Vadra demanded that the third girl be shifted to Delhi immediately for better treatment. “The Unnao incident is heart-wrenching,” she wrote in a Facebook post. “Hearing out the family and providing immediate medical help to the third victim is very important for investigation and justice.”

Congress chief spokesperson Randeep Surjewala took a swipe at the BJP government for its slogan of “Beti Bachao, Beti Padhao”.

Bahujan Samaj Party chief Mayawati, in a tweet in Hindi, expressed condolences to the family of the victims.