No injury marks were found on the bodies of the two teenage girls found dead in Unnao. The postmortem couldn’t ascertain the cause of their death said Uttar Pradesh Police chief, Hitesh Chandra Awasthi on Thursday.

The third girl, who was found in a field along with the two, is undergoing treatment at a Kanpur hospital and her condition is “critical but stable”, he said.

“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. 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,” Director General of Police (DGP) Awasthi said.

A medical bulletin issued by the Kanpur hospital treating the third girl has noted “it is a suspected case of poisoning”, the police chief said.

The three girls, aged 15, 14 and 16, left their homes to collect fodder on Wednesday evening. When they did not return, their family members went out, searching for them only to find them tied in a field in Babuhara village in Asoha, around 36 km south of Lucknow.

The villagers informed the police and rushed the girls to a local hospital where two of them were declared brought dead, while the third was rushed to the Unnao hospital and later referred to Kanpur.

The DGP said six police teams have been constituted and senior officials are supervising the probe, he said.