Prominent Chinese religious freedom advocate Pastor Bob Fu has filed a federal lawsuit in the US against a billionaire Chinese media executive.

Pastor Fu has accused Guo Wengui of stalking, defamation, conspiracy, and invasion of privacy. He claims that the media mogul has incited people to kill him and has harassed his family through online death threats and protests at his family home in Midland, Texas. 

Pastor Fu has said it all amount to a "multi-faceted campaign of character assassination" trying to silence him and stop his religious freedom and human rights work in China.

"Although claiming to support the Chinese pro-democracy movement, Guo employs his vast legal, financial, and corporate resources, together with his robust social media presence, to systematically target pro-democracy and pro-religious freedom activists in the Chinese American community," the lawsuit says. 

"Since 2018, Guo has attacked Chinese human rights activists and bona fide CCP (Chinese Communist Party) dissidents in the United States. This year, Plaintiff Bob Fu became Guo's latest target."

According to China Aid, Pastor Fu's persecution watchdog charity, Guo began the public attacks against Pastor Fu in September in a series of videos posted on his GTV and GNews websites, in addition to Twitter and YouTube. 

The charity claimed the attacks have become more aggressive in recent weeks with the promotion of death threats and protesting outside Pastor Fu's home. The protestors insist that Pastor Fu is a fraud and a spy for the Chinese government, information they got from Guo. 

The allegations, protests and threats against Pastor Fu have drawn the attention of local, state and federal law enforcement in the US, and drawn criticism from Senators Marco Rubio and Ted Cruz. 

China Aid said Pastor Fu and his family were recently placed in protective custody in separate locations.

"Dr Fu is an internationally recognized spokesperson for Christian ministry and religious freedom, and this abuse of his reputation and encouragement of violence against him must stop," says his attorney, Lawrence Wilson of The Lanier Law Firm in Houston. 

"His decades of dedicated promotion of human rights and democracy in his homeland and around the world must not be subjected to these assaults. This lawsuit will now shine a bright light on the actions and motivations of Mr. Guo."