A 25-year-old District man pleaded guilty yesterday to making a bomb threat against the Metro system that stopped all trains for 10 minutes on April 25, when thousands were traveling to an abortion rights rally on the Mall.

The same man, America Yegile Haileselassie, made a similar threat against Metro in February 2003, the U.S. attorney's office said. But a request for an arrest warrant filed by a Metro detective was not processed because "it was not a high priority" since there wasn't enough evidence to charge him in that case, said U.S. attorney's office spokesman Channing Phillips.

Haileselassie, of the 1200 block of Otis Street NE, pleaded guilty yesterday in U.S. District Court under a new federal statute that makes it illegal to issue a bomb threat against a mass transit system. It is the first case brought in this jurisdiction under the law. Haileselassie, who is deaf, faces up to 37 months in prison and a fine of up to $250,000 at sentencing, which is scheduled for Sept. 24.

Investigators said Haileselassie called Metro's communications center on a text telephone for the hearing impaired and made several threats to blow up trains. He was arrested four days later.

During the 30-minute phone exchange in April, Haileselassie informed the Metro dispatcher that he paid four people to plant numerous bombs that would explode at noon "where there will be a lot of people," according to the U.S. attorney's office. He also threatened to kill President Bush.

The threat came on the day of the March for Women's Lives, when 405,163 riders were on the Metro system, many of them headed for the Mall.

Transit Police Chief Polly Hanson said canine units swept every train before the subway opened and all 83 stations and found nothing. As the noon deadline approached, Hanson said, she decided to hold all trains in their stations for 10 minutes but opted not to evacuate the system or shut it down.

"I had no reason to do that -- we already checked the stations and the trains, and I had no specific threat," Hanson said. "But at 11:45 a.m. I'm thinking, what else can I do?"

If there had been an explosion, keeping trains inside stations would make evacuation easier than if they were inside tunnels deep below ground.

Metro officials announced to passengers a "pause in service" and recommended that riders in the downtown area consider walking to their destinations. Transit police and managers told passengers the pause was needed to alleviate congestion. "We don't tell people that there's bomb threats," Hanson said. "The more you advertise that, the more some people get an idea. . . . I tried to accomplish the same thing in a different way without alarming people or promoting similar acts in the future."

Hanson said the subway was never closed and the public was not stopped from entering stations. After 10 minutes, when the noon deadline had passed, the trains resumed operation, Metro spokeswoman Lisa Farbstein said.

The investigation into the threat, which involved the Secret Service, FBI and D.C. police, was familiar to the transit police. Last year, a detective filed an application for an arrest warrant for Haileselassie after collecting evidence that he was behind a Feb. 3, 2003, bomb threat against the Anacostia Metro station, Hanson said.

In that case, Haileselassie was caught on videotape at the Anacostia Station when he placed a 2:30 p.m. call to D.C. police and threatened to blow up the station, Hanson said. She said the application for a warrant was filed with the U.S. attorney's office in February 2003.

Phillips, spokesman for the U.S. Attorney Roscoe C. Howard Jr., said prosecutors sought more information from the detective before approving the warrant. The information was provided, but by then Haileselassie was at St. Elizabeths Hospital, where he lived for seven months.