Three parking lot attendants at the Smithsonian's National Air and Space Museum have been arrested in a scheme that allegedly cost the Chantilly annex $400,000 in lost parking revenues.

Freweyni Mebrahtu, 45, of Sterling, Meseret Terefe, 36, of Silver Spring, and Genete Yigzu, 46, of Alexandria, were charged with embezzling and stealing federal money belonging to the Smithsonian Institution, according to the U.S. Attorney's Office for the Eastern District of Virginia.

Each faces up to 10 years in prison if convicted.

The trio was arrested by agents of the Smithsonian Office of Inspector General and the FBI late Saturday after finishing their shifts at the Steven F. Udvar-Hazy Center in Chantilly.

The National Air and Space Museum annex is home to the space shuttle Discovery, the Enola Gay bomber and other historical aircraft that cannot be displayed at the museum on the National Mall.

The two sites showcase the largest collection of aviation and space artifacts in the world.

Smithsonian spokeswoman Linda St. Thomas said Monday that she could not comment about the case because it was an ongoing investigation.

According to charging documents, the trio began stealing in April 2009 shortly after Parking Management Inc. took over management of the Udvar-Hazy Center's 2,000-vehicle parking lot.

The facility gets more than 1 million annual visitors who pay a $15 daily fee per vehicle if they use the parking lot. An electronic device inside the attendant's booth counts each time the lot's gate arm rises to let a vehicle through.

Closed-circuit security cameras captured Mebrahtu, Terefe and Yigzu repeatedly unplugging electronic vehicle counters to manipulate the total, court documents said.

By unplugging the counters, the attendants collected money for vehicles that were never recorded electronically, charging papers said.

Terefe was also observed hiding a bundle of cash taken from the entrance fees in a side pocket of a red duffel bag that he carried from the parking facility at the end of his shift, prosecutors said.

On some days, Mebrahtu and Terefe stole more than $4,000 from the Smithsonian by undercounting up to 298 visitor vehicles a day, documents said. Yigzu is accused of stealing as much as $1,185 on a single day.