Speaking at the Global Konkan Festival in Mumbai Saturday evening, he said the gang-rape of the 23-year-old woman was sad and nobody should ever face such a situation.
"However, nobody is willing to go to the root of the matter and reveal who committed the heinous crime. They were all from Bihar," Thackeray said.
The MNS chief said that whenever he raised the issue of Bihari criminals, he was abused, but now even Delhi Chief Minister Sheila Dikshit has commented on the matter.
"She (Dikshit) said in the presence of Prime Minister Manmohan Singh and Congress president Sonia Gandhi that migrants in Delhi were responsible for the spate of criminal activities," Thackeray said.
Taking umbrage at Thackeray's remarks, Bihar BJP leader and Animal Husbandry Minister Giriraj Singh said the MNS leader has lost his "mental balance" and sought a ban on his party.
Former union minister and RJD chief Lalu Prasad Yadav also criticised Thackeray's statements, saying that the MNS chief "has a habit of speaking in this manner".
Janata Dal-United leader Ali Anwar said Thackeray's statement was appalling and "he has gone mad". He challenged Thackeray to make such statements outside Mumbai or Maharashtra and then watch the consequences.
Congress spokesperson Rashid Alvi condemned the statement in New Delhi saying that it was "unfortunate and served to weaken the country and its democracy".
In Maharashtra, the Congress hit back by terming Thackeray's statements as "irresponsible and deplorable".
State Congress spokesperson Sachin Sawant said there have been several instances when MNS workers and leaders have been involved in criminal activities.
"Last month, an MNS leader was arrested by Vikhroli police for raping a minor girl. Three years ago a minor housemaid was gang-raped by four MNS workers. An MNS leader was arrested for the rape of a girl in Amravati in April 2011. Thackeray is bereft of issues and is resorting to such statements to divert attention from his partymen's actions," Sawant said in a strongly worded statement Sunday evening.
In the past, Thackeray had said that migrants and Biharis were responsible for the growing criminal activities in Mumbai and other parts of the state.