A 27-year-old District man was sentenced to 20 months in prison for making bomb threats that delayed more than 1,000 Amtrak passengers.

Michael Jerome Dennis, who pleaded guilty in August 2012 to a charge of threatening to convey false information about an attempt or alleged attempt to use a destructive device, was also sentenced to five years of supervised release, federal prosecutors said.

Dennis admitted that he called Amtrak’s national communications center in November 2011 and January to report that a bomb had been placed on the Amtrak bridge over New York Ave NE.

Federal prosecutors said the threats forced authorities to thoroughly search the area and to delay six trains, which affected more than 1,000 passengers.