"Witness Pandurang Adarkar who is from Kolhapur in Maharashtra has been detained. He has confessed to being witness to the murder of one Shanu Gaonkar, who is missing since 2006," said inspector Dipak Pednekar.
In the video, Adarkar purportedly claimed he was witness to Rane shooting Gaonkar dead in Sattari tehsil of Goa in 2006 to avenge the killing of his brother Prithviraj Rane.
Prithviraj was murdered at Saleli village of Sattari tehsil in 2005.
No one had been arrested yet, but the statements of all the people named by Adarkar would be recorded, he said.
The police officer, however, ruled out questioning Rane at this juncture.
Vishwajit Krishnarao Rane could not be reached for comments. He contested the Assembly election earlier this month on the BJP ticket against Congress' Pratapsinh Rane from Poriem constituency.