Roger Federer, the world's number one tennis player, received a death threat in China Thursday.
As a result, the Shanghai Masters organizers have tightened security around him.
Blue Cat also also posted a "doctored image showing a decapitated Federer on his knees on a tennis court, with a masked executioner dressed in black and holding an axe posing next to him."
The police, government officials, and tournament organizers are taking this very seriously placing extra security around Federer and his family.
Although attacks on tennis players are rare, they aren't unheard of.
In 1993, Monica Seles was stabbed by a Steffi Graf fan in Hamburg, Germany
