A California man pleaded guilty this week to sending more than 150 bizarre, threatening or hoax letters in 2017 to President Trump and to former presidents, FBI offices and other individuals and businesses, according to reports.

Kao Xiong, 34, a former Amazon employee from Oroville, allegedly sent the letters, which contained bomb threats, death threats, assassination threats and extortion demands, prosecutors said. Some envelopes contained a white powder that turned out to be flour, the Sacramento Bee reported.

“I need one million dollars or Donald Trump is dead,” two letters said, according to the Chico Enterprise-Record.

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“I need one million dollars or Donald Trump is dead.” — Threat that appeared in two letters, according to court papers

Other targets included former presidents George W. Bush, Barack Obama and Ronald Reagan -- who was dead 13 years at the time -- the Mall of America and the headquarters of Yahoo, court papers said.

“Pipe Bomb, Everyone is going to die,” one letter mailed to Texas read, according to court records.

In a federal courtroom in Sacramento, Xiong pleaded guilty to a single count of conveying false information concerning use of an explosive. He faces up to 10 years in prison.

His lawyer, Tim Zindel, described the case as “just a touch of mental illness" after his client admitted in court to previously being treated for mental problems.

In two letters sent November 2017 to Hmong TV in Minnesota and the FBI Boston’s field office, Xiong demanded $1 million be dropped off at a McDonald’s in Minnesota, according to court records.

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No evidence was found that indicated Xiong ever built any device, and he told investigators he had no access to explosives training or any intent to hurt anyone.

In a separate case, Florida resident Cesar Sayoc has been charged in connection with a string of mail bomb packages sent late last year to Trump critics and prominent Democratic figures.