Hewlett Packard Co rebuffed a request by former Autonomy Chief Executive Mike Lynch to detail accusations of accounting fraud leveled against the British software company and its former executives, and challenged Lynch to submit to questions under penalty of perjury.

HP was responding to an open letter that Lynch shot to HP’s board on Tuesday, asking for specifics of the U.S. company’s allegations that Lynch and former Autonomy executives inflated revenue and gross margins, which HP said last week forced it to take an $8.8 billion writedown on Autonomy’s value.

It really appears that both sides think they have something on the other. If Lynch really did do something, wouldn’t he just go hide and count his money? Now HP ups the ante with its “penalty of perjury” request.

It’s hard to know who has the upper hand here.