A day after a mysterious object fell from the sky near Thirukazhukundram and created a panic among Vadakkupattu villagers, the police identified it as a sonobuoy — an equipment used to study  underwater acoustic research.

Immediately after the object was spotted on Monday evening, the Chengalpattu district police had taken it to a secure location on Monday night.

The sonobuoy had possibly fallen off an aircraft carrying out research on sea ecosystem. The Indian Navy usually carries out such studies.

A police officer said, "It is not clear from where the equipment came but it will be easy to trace the origin with its batch number and other details printed on the body."

The 3-foot long cylindrical object was discovered by a 55-year- old man from Vadakkupattu village, who was walking in the fields with his goats. Venkatesan claims he saw the object fall from the sky with a loud bang on Monday afternoon.

He initially thought the object was an explosive and alerted the VAO and other villagers. Soon the VAO and the Thirukazhukundram police arrived at the spot. The police later took the item away for safekeeping and identification.