SAN FRANCISCO (CBS SF) — A federal grand jury has indicted former inmate Vladislav Victorvic Timoshchuk for allegedly sending a ricin-laced envelope to the warden at Pelican Bay State Prison.

Timoshchuk was a former inmate in the California state prison system who was deported back to his native Belarus. Federal prosecutors did not identify which state prison he had been housed in, but the letters were linked to demands for the release of a current Pelican Bay inmate only identified as “A.C.”

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According to the indictment, the 34-year-old who still resides in Belarus, is alleged to have sent two envelopes containing ricin to Pelican Bay State Prison.

One of the envelopes was addressed to Warden James Robertson and contained ricin and a note which read: “WARNING! TOXIC! THIS LETTER IS LACED WITH DEADLY RICIN POWDER.”

The other envelope was addressed to inmate A.C. and contained ricin and a note, which read in part: “Release inmate A.C.”

The indictment further alleged that in 2016 and into 2018 Pelican Bay prison officials intercepted letters postmarked from Belarus to members of a prison gang, including to inmate A.C.

Federal prosecutors also revealed that the Anaheim Police Department investigated a 2017 school shooting threat, which demanded the release of inmate A.C. from Pelican Bay State Prison in order to avoid the “execution” of a student every day until that release occurred.

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Later, in 2019 the Bureau of Prisons intercepted a Christmas card sent from Belarus to inmate Theodore Kaczynski, the infamous Unabomber, in which Timoshchuk claimed responsibility for the threats to Anaheim schools and discussed a plan to mail ricin to the United States.

Thursday’s indictment charged Timoshchuk with two counts of attempted transfer of a toxin for use as a weapon; two counts of interstate and foreign communication of a threat and two counts of mailing an injuries article.

He was not charged for any other threats than the two mailings to Pelican Bay.

If convicted, Timoshchuk could be sentenced to a maximum sentence of life for each attempted transfer of a toxin for use as a weapon; a maximum of five years for each interstate and foreign communication of a threat; and a maximum sentence of one year for each mailing of an injurious article.

According to California corrections officials, Timoshchuk was sentenced in San Diego County on May 8, 2006, to serve five years for second-degree robbery and sentenced on May 16, 2006, with a six-year sentence for second-degree robbery; the sentences were to be run concurrently.

He was then sentenced on Nov. 4, 2006, in Yolo County with a one-year, four-month sentence for vehicle theft, acquiring/retaining an access card/account information without consent, and battery on a peace officer.

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Timoshchuk was admitted to state prison on June 6, 2006; released to parole on Jan. 18, 2011; and discharged from parole supervision on July 21, 2011. He was then deported back to Belarus.