The incident happened on Tuesday evening at Nagabali river on the outskirts of Rayagada.
The woman had gone to a suspension bridge on the Nagabali river with her family, Inspector In-Charge of Rayagada police station Rabi Patra said.
After taking a few photographs on the bridge, the woman along with her son and daughter climbed down from the bridge, positioned themselves on a rock beside the river, and starting taking selfies, the police officer said.
While taking a selfie on a rock, the trio slipped and fell into the water, the IIC said.
The boy had gone missing, Mr Patra said, adding, his body was fished out today.
The deceased were identified as 30-year old J Shanti and five year old J Akil, Patra said.
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