Shrimant Patil is being treated at state-run St George Hospital in South Mumbai.
Mumbai police on Friday allowed Karnataka police officials to meet Congress MLA Shrimant Patil, who has been admitted in a state-run hospital in the city.
The police officials from the southern state recorded Mr Patil's statement, an official said.
The development came amid reports that Mr Patil wrote to Karnataka Assembly Speaker K R Ramesh, denying that he was kidnapped by the BJP.
"I went to Chennai for personal work and felt chest pain. Visited hospital and on doctor''s suggestion I came to Mumbai and got admitted here. I was not kidnapped by BJP," Mr Patil wrote in an email to Ramesh, sources said.
Mumbai police provided security to Mr Patil, the legislator from Kagwad in Belgaum district, who arrived in the city on Thursday and was hospitalised after he complained of chest pain.
He was first admitted in a private hospital and later shifted to state-run St George Hospital in South Mumbai, the official said. "We have provided security to the MLA and his statement was recorded," an official said.
The Congress had alleged Shrimant Patil had been "kidnapped" as part of efforts to "topple" the coalition government in the southern state.
Congress leader and Karnataka minister D K Shivakumar had said they would produce documents to show Mr Patil was forcibly admitted to the hospital to skip the trust vote in the Assembly.
According to sources, 15 rebel MLAs from the Congress and JD (S) are camping at a luxury hotel in Mumbai.