A Connecticut man who pleaded guilty last year to a series of hoaxes, including sending a letter with white powder threatening to kill then US President Donald Trump, was sentenced to nine years in prison, The New York Times reported.

Gary Joseph Gravelle, 53, of New Haven, pleaded guilty to seven charges related to threats he made in September 2018, according to John Durham, the US attorney in Connecticut.

In early September 2018, Gravelle sent a threatening letter addressed to Trump accompanied by a white powdery substance that Gravelle claimed was anthrax, according to court records. Other recipients of Gravelle’s threatening messages included federal probation officers, mental health providers and a credit union. He also threatened to blow up planes and property at the Burlington International Airport in Vermont.

Judge Kari Dooley of US District Court in Bridgeport, Connecticut, sentenced Gravelle to more than seven years in prison for the threats he made in 2018 and an additional two years for violating conditions of his release.

Gravelle has been incarcerated since his arrest Sept. 8, 2018, and had previously been jailed for sending threatening messages in 2010, according to Durham’s office.

His guilt or innocence has never been much disputed, according to officials and Gravelle’s lawyer.