The Karnataka Congress has made its complaint of the BJP allegedly trying to buy its lawmakers official. The party's legal cell on Thursday complained to the state's anti-corruption bureau against BS Yeddyurappa and five BJP leaders, accusing them of offering bribes to lawmakers of the Janata Dal-Congress alliance ahead of Mr Yeddyurappa's trust vote last week.

The Congress, which handed over the complaint just a day after HD Kumaraswamy took oath as Chief Minister, has also submitted a copy of the phone conversations recorded by its lawmakers to back up its charge.

The party had released the audio tapes that Congress leaders had alleged, were evidence that BJP leaders including Mr Yeddyurappa had allegedly trying to bribe lawmakers to switch sides.

In some, there were hints of the lawmakers being offered money and ministerial berths. One tape, according to the Congress, also had Janardhan Reddy, the scam-tainted mining baron disowned by BJP president Amit Shah, allegedly offering money and posts to a Congress legislator for his support.

The BJP had then rubbished the tapes, claiming these were fakes and the Congress had hired mimicry artistes.

The anti-corruption branch hasn't registered a case yet. But the Congress decision to file a complaint with the anti-corruption branch is seen as a reflection of the confidence of Congress leaders to get experts to rule on the authenticity of the audio tapes.

Apart from Mr Yeddyurappa, the Congress's complaint also names his son Vijayendra, BJP's national general secretary in-charge of Karnataka Muralidhar Rao, mining baron Janardhan Reddy, his close aide and lawmaker B Sriramulu and legislative council member BJ Puttaswamy.

The six and others, the complaint alleges, entered into a conspiracy to bribe the legislators.

Mr Yeddyurappa had been controversially invited by Governor Vajubhai Vala to form the government and prove his majority within 15 days. The BJP had emerged as the single largest party in this month's assembly elections with 104 of the 221 seats on which elections were held. The JDS-Congress combine had 115 seats but its claim was ignored.

The Supreme Court, on a petition filed by the Congress, ordered him to take the trust vote on Saturday. The Congress-JDS alliance also sequestered its lawmakers in hotels in Hyderabad to make sure the BJP couldn't influence him.

Mr Yeddyurappa stepped down from the chief minister's post without facing the confidence vote that he would have lost.

The Congress complaint also cited his exit speech in the assembly, claiming that Mr Yeddyurappa also substantiated its allegation when he admitted to reaching out to non-BJP lawmakers for support.