Computer and printer maker Hewlett-Packard (HP) has responded with a legal threat to an angry letter from Mike Lynch of former Autonomy.

HP had accused Autonomy is indulging in misleading accounting practices during the merger negotiations between the two companies in 2011. Autonomy, which was established in 1996, grew from its origins to become one of Europe's largest and fastest-growing software companies. It was acquired by HP in October 2011 for more than $11 billion following negotiations between the two companies.

CEO Meg Whitman claimed during a conference call that former Autonomy used misleading accounting and also kept key information secret during its negotiations with HP about the merger in 2011. HP and former Autonomy executives have exchanged in a serious and heated exchange of comments.

Mr. Lynch wrote an angry letter to HP asking the company to explain its highly damaging allegations. HP had revealed last Tuesday in a statement that its "internal investigation and forensic review uncovers

accounting improprieties, misrepresentations and disclosure failures in Autonomy financial statements

prior to 2011 acquisition by HP."

"The matter is in the hands of the authorities, including the UK Serious Fraud Office, the US Securities and Exchange Commission's enforcement division and the US department of justice, and we will defer to them as to how they wish to engage with Dr Lynch. In addition, HP will take legal action against the parties involved at the appropriate time," HP said.