A man prosecutors said had a history of threatening Hawaii Rep. Tulsi Gabbard has been sentenced to nearly three years in prison.

Prosecutors said Monday that 44-year-old Aniruddha Sherbow has been sentenced to 33 months. Sherbow entered a plea of nolo contendere in February 2014 to two counts of making threats.

Under a nolo contendere plea, a defendant is convicted, accepts responsibility and agrees the government could prove him guilty beyond a reasonable doubt but does not admit to the facts of the case.

Sherbow has also been ordered to pay nearly $540,000 in restitution to the U.S. government for security expenses incurred as a result of his threats.

Sherbow’s attorney said Sherbow has severe mental health problems that are at the root of his conduct.