Sentence:  Two years after he received his piece of the Nobel Prize, Mann was drawn into controversy over a series of e-mails stolen from the University of East Anglia in the United Kingdom that some climate change skeptics charged provided proof that Mann and his fellow scientists were <WSD>cooking the books</WSD> on climate, though for what reason, the skeptics never made clear. 
Meaning of the word marked with <WSD> tags:  To falsify an account of an event.