The arrestees were identified as Sujon Khan, 30, father of victim Sohana, Ripon Khan, 24, brother of Sujon and Hasib Khan, brother-in-law of Sujon.
They were interrogated on Wednesday by a team of police at Morelganj Police Station and later they were shown arrested in a case filed over her death, said Pankaj Chandra Roy, superintendent of Bagerhat Police.
Dr KM Humayun Kabir, Bagerhat Civil Surgeon, said an autopsy of Sohana was conducted at Bagerhat Sadar Hospital on Wednesday.
As per the autopsy report, an injury mark was found on the head of Sohana and she died due to excessive bleeding , said Dr Humayun.
On Tuesday, police recovered the body of Sohana, who was reportedly stolen from her parents while asleep early Monday, from a pond near their house at Gabtola in Morelganj upazila of the district.
A case was filed with Morelganj Police Station on Monday night.
According to the case statement, Sujon along with his wife Shanta Begum went to bed with their 17-month –old daughter Sohana on Sunday. Around 1:30 am, Shanta suddenly woke up and found their daughter missing.
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