Police said investigations began after the girl's grandmother complained (Representational)

The body of a 16-year-old girl, who went missing two weeks ago, was found inside a well in Thiruvananthapuram district and police have arrested her mother and lover from Tamil Nadu.

The body was found in a highly decomposed state from an unused well at Nedumangad Saturday.

Police said investigations began after the girl's grandmother complained that her granddaughter and daughter were missing, police said.

"We got a complaint from the grandmother of the victim that the child and the mother were missing. We found the mother and lover at a place in Tamil Nadu. When we interrogated them, they told us where the body was dumped," an investigating officer told PTI.

He said initially the mother told the police that the girl was found hanging in her room and the duo disposed of the body out of fear.

"We are yet to ascertain the reason for the death. The body was in a decomposed state. We are waiting for the post-mortem report," he said.

The woman was estranged from her husband.