The police have arrested Mamata, her paramour Rakesh Kumar and one Ajeet Kumar for killing the toddler and then burying the body near their house.
Mamata had left her husband Virendra Yadav and her child to live with Rakesh, said official sources.
She used to keep the child with her in the absence of Yadav. This, however, became a bone of contention between her and Rakesh as the latter disapproved the presence of the child at their home.
Rakesh believed that Yadav was using their child to convince Mamata to stay with him.
As Yadav enquired about their son on his return, he was told that the child lost his life in a fatal illness.
Being suspicious about his wife, he approached the police and after a brief investigation arrested all the three culprits.
A case has been registered in this regard and further probe is on. (ANI)