More lambs have been stolen in the area, with 48 taken from fields near Llandinam.
Last month police revealed a similar theft and have urged farmers and landowners to be vigilant.
In the latest case, 48 lambs were stolen between 20 and 30 November from the fields near the village.
"We are asking the public to remain vigilant, check and secure the gates to any land containing livestock and report any suspicious activity to the police immediately," said PC Hannah Thrower of Llanidloes Police.
"If anyone has any relevant information that can assist with this investigation, please contact PC 491 Thrower at Llanidloes Police Station by telephoning 101."
