The CBCID has summoned one person in the Vengaivayal case where human faeces were mixed into the water tank at the village in 2022.
The agency has been investigating the case for more than a year and has questioned 221 people. Thirty-one were taken for DNA tests and five for voice test.
CBCID DSP Kalpana Dutt is investigating the case.
Sources said that one person from Venagivayal village in Muttukkadu panchayat had been issued summons to appear before the Pudukottai CBCID office for an inquiry on Thursday.
