More than 200 tax investigators in India have searched the offices of a number of contractors used in the run-up to the Commonwealth Games.
The raids in Delhi came as the main opposition party, the Hindu nationalist Bharatiya Janata Party (BJP), demanded a parliamentary investigation.
The Games, which ended last week in Delhi, were marred by spiralling costs and allegations of corruption.
The BJP says it has evidence of wrongdoing at government level.
'Very big scam'
Income tax officials swooped on the offices of contract companies in and around Delhi on Tuesday, seizing documents relevant to any work associated with the Games.
Among the addresses raided was the residence of a businessman and prominent BJP activist, according to Indian media.
The BBC's Chris Morris in Delhi says that now the Games are over, the political fight is beginning in earnest.
The Congress party-led government has already set up an inquiry, led by its urban development minister, into the event, promising anyone found guilty will be punished.
The BJP says millions of dollars were siphoned off from the Games budget, which ballooned to $6bn (£3.8bn), from an original estimate of $450m.
The opposition party alleges corruption in the building of sports facilities in particular.
BJP President Nitin Gadkari told reporters in Delhi that the Games had been a "very big scam".