The claim was shocking: had Robert Vadra, son-in-law of Congress president Sonia Gandhi, really been involved in illegal sweetheart deals with a property company, DLF? And had DLF really received undue favours from the Congress-run state government of Haryana?
The allegations, made early this month by whistle-blower-turned-politician Arvind Kejriwal, brought a standard denial from the 43-year-old Mr Vadra: "I am a private law-abiding citizen who has been engaged in business over the last 21 years. The allegations levelled against me ... are utterly false".
But then, on his Facebook account, he added this: "Mango people in a banana republic."
In Hindi, "mango people" sounds like "common man". Everybody claims to be the common man - the phrase is part of the slogan of Mr Kejriwal's activist group India Against Corruption, but is also used in Congress party rhetoric and literature. Mr Vadra seemed to be calling India a banana republic, thereby poking fun at his own mother-in-law.
The Facebook post was soon taken down but the damage had been done. In India, small things like this still matter. Indians expect those in public life to behave with a modicum of courtesy, especially if they want respect as well as votes.
Mr Vadra is not a politician - except that his wife Priyanka is the granddaughter of Indira Gandhi and the daughter of Sonia Gandhi, India's most important politician. Married into this family, Mr Vadra is a public figure by any measure.
And so his ill-chosen quip fuelled suspicion that there is something not totally right about his dealings with DLF, a property giant. Mr Vadra, a small-time dealer in brassware a few years ago, has now become a considerable property tycoon.
According to one of Mr Kejriwal's accusations, the Haryana government allotted 142 hectares of land to DLF to build a hospital, but DLF built a special economic zone instead, and a year later Mr Vadra was given a 50 per cent stake in it. Moreover, Mr Kejriwal said, DLF gave Mr Vadra an unsecured interest-free loan worth Rs650 million (Dh45million), money he used to buy luxury apartments at a fraction of their value.
Such claims are all too familiar. India's rapid economic growth in the last two decades has come about in what can only be called a climate of corruption. In the last three years alone, all major political parties have been tarnished by scandals in which the state is said to have lost more than $100 billion in revenue. These include a $35 billion coal-mine-rights allocation case; the $37.8 billion Karnataka Wakf Board land scam; and the $33.26 billion 2G spectrum scam, in which the Dravida Munnetra Kazhagam party was said to have been the lead beneficiary.
Last month another case arose. Anjali Damania, Mr Kejriwal's ally in India Against Corruption, accused the BJP party president, Nitin Gadkari, of refusing to inquire into a $13.6 billion irrigation fraud in Maharashtra state. The Congress and the Nationalist Congress Party are in power in Maharashtra; the BJP is in opposition and so should have been interested in the scandal allegations. However, Ms Damania claimed that Mr Gadkari had admitted to her that he had business interests with Sharad Pawar, a senior politician of the Nationalist Congress Party, and so would not pursue the issue.
Mr Gadkari, denying wrongdoing, has sued Ms Damania for her comments.
Through all these cases, the sticky finger of blame has until now always pointed away from the Gandhi family. When Mr Kejriwal began to gun for Mr Vadra, it seemed as if a barrier had been breached.
On the eve of the winter session of parliament, battle lines are being drawn. But nobody has been able to explain why the Corporation Bank, a public-sector firm, loaned Mr Vadra's companies money to help purchase some of his DLF land, when the bank's directors have stated nothing of the sort happened.
For the time being, the accusations against Mr Vadra are nowhere near the scale of the Bofors scandal of the 1980s and 1990s. That affair, over which then-prime minister Rajiv Gandhi was accused of colluding in kickbacks from the purchase of artillery, lost him the 1989 election.
But in the current highly unstable political situation, the wind could end up blowing in any direction. In India, the season of political discontent seems to have only begun.
Jyoti Malhotra is a political and foreign affairs analyst based in Delhi
On Twitter: @jomalhotra