HP is to sue Sushovan Hussain, the former chief financial officer of Autonomy, claiming that he "was one of the chief architects of the massive fraud" at Autonomy.
In a filing with the US District Court of the Northern District of California on Monday, HP lambasted Hussain and described HP as "the victims".
The filings were made in opposition to a motion by Hussain's lawyers to block HP settlements in three shareholder lawsuits. Hussain sought to block that settlement arguing that it wrongly absolved HP executives for their decision to acquire Autonomy at a price widely regarded as excessive. HP later wrote down $8.8bn of the $11.1bn purchase price.
However, HP's lawyers claim that the move by Hussain is a legal manoeuvre to "obtain discovery [of internal HP documents] that he hopes will help him stay our of prison and defend the civil litigation he expects HP will file in the UK".
It continued: "Hussain also knows that prosecutors on both sides of the Atlantic are investigating him, that HP is cooperating with those authorities and that, until he is charged, he has no access to the information that HP is providing to the authorities.
"So Hussain, the fraudster, wraps himself in a mantle of self-righteousness in an attempt to obtain discovery that he hopes will help him stay out of prison and defend the civil litigation he expects HP will file in the UK."
However, in a statement to Reuters, Lynch accused HP of buying off the shareholder groups that were suing the company over the botched deal.
"This breathless ranting from HP is the sort of personal smear we've come to expect. As the emotional outbursts go up, the access to facts seems to go down. Meg Whitman is buying off a bunch of lawyers so she doesn't have to answer charges of incompetence and misdirection in front of a judge and jury," claimed Lynch.
The filings indicate that HP is planning no let-up in its action against the former management of Autonomy, the search technology software company that HP paid $11.1bn for in November 2011 - a deal that Oracle flinched at half the price. HP subsequently took an $8.8bn write-down after an audit suggested that the company had overstated its UK profits by 80 per cent and its revenues by 50 per cent.
HP claims that Lynch and Hussain engaged in fraud by false accounting by, for example, recognising software revenues in deals involving bundled hardware and "channel stuffing". Lynch and Hussain argue that Autonomy's accounts were not only signed off by the company's auditors, but also passed HP's own due diligence process.
Lynch has consistently denied HP's accusations and accused its CEO, Meg Whitman, who was on the board of HP at the time of the acquisition and waived it through when she was promoted to CEO, of incompetence.