A man already serving time for a murder almost 10 years ago was just convicted of threatening a California federal judge.

At a sentencing hearing set for May 14, California inmate Eric Anthony Lopez is looking at up to ten years for threats he made against U.S. District Judge Irma E. Gonzalez.

Lopez, who is currently serving 25 years in prison for a first-degree murder conviction from 2003, sent a threatening letter to Judge Gonzalez, saying he would eliminate her using anthrax.

He face up to 10 years and a $250,000 fine.

In the letter, Lopez also told the judge he would introduce her to the “grim reaper.”

Last week a San Diego jury convicted Lopez, though the Department of Justice did not make the announcement until Tuesday.