"The forefathers of the Thackerays hailed from Bihar and migrated to Mumbai generations ago as has been corroborated by a book written by a late Thackeray family member," he told PTI.
"If the Bihari migrants are infiltrators in Mumbai as described by Sena leaders and MNS chief Raj Thackeray, then the Thackerays themselves are infiltrators," Prasad said.
Thackerays should stop calling the Bihari migrants as infiltrators as their Bihari ancestry has been proved or otherwise they took risk the prospect of being thrown out of Mumbai.
It may be mentioned that the senior Congress leader Digvijay Singh had quoted from a book written by MNS chief's grandfather Prabodhankar Thackeray stating that Thackerays' ancestors were natives of Magadh region of Bihar before shifting to one place to another enroute to finally settling down in Maharashtra.
The MNS chief Raj Thackeray had retaliated and debunked the Congress leader's remarks describing the Thackerays as Biharis.
