Story highlights Investigators looking into the scandal noticed an odd thing

The alleged forgery adds weight to calls for Pakistan PM to step down

Islamabad, Pakistan (CNN) The Microsoft font Calibri could be an unlikely smoking gun in a corruption scandal which has mired Pakistan's ruling family and captivated the country.

The scandal centers around allegations that Prime Minister Nawaz Sharif's family owns properties in London through offshore companies. And while owning property in itself is not illegal, opposition parties have questioned if the money to buy them came from public funds.

Last November, the Prime Minister's daughter, Maryam, tweeted images of a disclosure form claiming she wasn't the real owner of the apartments.

She said the documents proved she was a "trustee and not the owner" of the properties.

2nd trust deed:

I am a trustee & NOT the owner. Proof attached. #TheTruth pic.twitter.com/ATfonbEw8Y — Maryam Nawaz Sharif (@MaryamNSharif) November 15, 2016

Investigators looking into the scandal noticed an odd thing.