A Boulder man accused of sending letters containing a suspicious white powder to two Jewish organizations in the Colorado city pleaded guilty.

Jeffery Thomas Klinkel, 34, pleaded guilty late last month to one count each of felony menacing and using a hoax chemical or biological weapon, the Daily Camera reported Monday. He will be sentenced on June 1 and faces up to five years in prison.

On April 6, 2015, the Boulder JCC received a letter that read, “This Goyim is enjoying the blood of her enemies for Passover” and contained a suspicious white powder later determined to be cornstarch.

Soon after, on the same day, Congregation Har HaShem received a similar letter with the white powder. Klinkel’s fingerprints were found on both letters.

At the time, employees who came in contact with the letters were put under quarantine.

Klinkel has an extensive criminal record that includes arrests for assault, harassment, burglary, trespassing and fraud.