The victim 46-year old S Dhanasekar was a headmaster in a government school and his wife Sumathi was also a teacher in another government-aided school, both in Tiruvarur district.
Sumathi had, along with Rajan, allegedly poisoned to death her husband on May 14 at their house in Marakadai.
S Kannadasan, brother of the victim, claimed that soon after his brother's death, Sumathi herself admitted to the crime to family members, 'pricked' by conscience. Later, she confessed to the crime in the TV show a few weeks ago.
Police said murder charge has been slapped against Sumathi and Rajan.