The Microsoft font Calibri is now a key piece of evidence in a corruption investigation surrounding Pakistan’s prime minister. Investigators noticed that documents handed over by the prime minister’s daughter, Maryam Nawaz Sharif, were typed up in the font Calibri. But the documents were dated from 2006 — and Calibri wasn’t widely available at that point, making a good case that they were forged.

The Express Tribune says that Pakistan’s court-appointed investigators sent the documents off to a lab for examination. The lab noticed the discrepancy, with one of its experts saying that since “Calibri was not commercially available before 31st January 2007 ... neither of the originals of the certified declarations is correctly dated and happy [sic] to have been created at some later point in time.”

How many people were actually using Calibri in 2006?

There is still some complication here. Calibri was in existence before then, just in a very limited means. Sharif, who has said she rejects the report’s findings, has retweeted a screenshot of a Quora page saying that Calibri had been available in a Windows beta as early as 2004. It’s not clear that date is accurate, but Calibri does appear to have been available in some limited form at the time her documents are alleged to have been created.

Dawn asked the design company that created Calibri about the timeline. The company said that Calibri was delivered to Microsoft in finished form in 2004 and that the first public betas to include it were released in 2006. “We do not know the exact date for this public release date [but] it is [still] extremely unlikely that somebody would copy fonts from a beta environment to use in official documents," said a representative for LucasFonts.

The investigation goes back to the 2016 Panama Papers leak, which revealed details of customers using a law firm to handle offshore accounts. The children of Pakistani Prime Minister Nawaz Sharif were among those customers, and they showed holdings that the Sharif family had failed to publicly declare. The country’s Supreme Court ordered a group of investigators to look into the matter, culminating in the report produced this week.

Investigators believe that his family had more assets than they declared and faked documents to hide it, according to Reuters. There are now calls for the prime minister to resign, though it appears that he intends to see the court case through. “Every contradiction will not only be contested but decimated in [the Supreme Court],” his daughter wrote on Twitter.