MOSCOW, May 23 (RAPSI) - US authorities Wednesday arrested a man charged with mailing letters containing the deadly poison ricin to a US federal judge in Spokane, Washington, as well as a local postal official, the Fox News channel said on its website.

The letters containing the dangerous substance were intercepted last week during a screening process at the post office. According to the postmarks, both letters were mailed on May 14.

On Wednesday the police arrested Matthew Ryan Buquet, 37, from Washington, who was then charged with mailing threatening communications, including to US District Judge Fred Van Sickle.

The suspect has denied the charges.

In April, the authorities intercepted a batch of letters containing ricin addressed to President Barack Obama and other federal officials, including US Senator Roger Wicker (Republican - Mississippi) and Senator Carl Levin (Democrat - Michigan).

FBI agents arrested and charged James Everett Dutschke after they found a dust mask that tested positive for ricin and also contained Dutschke's DNA. They believe he left the traces while preparing the poison.