The man described by prosecutors as the “leader and organizer” of a group that terrorized high-end retailers in the D.C. area and Pennsylvania during a spate of smash-and-grab robberies was sentenced to 20 years in prison Friday as federal court proceedings were getting underway against several alleged accomplices.

Prosecutors said Walter Douglas, 34, had been a criminal for “essentially his entire adult life” and had played a pivotal role in managing a group that committed 28 robberies of high-end retailers in Northern Virginia, Maryland and Pennsylvania last year and early this year.

Special Assistant U.S. Attorney Edward Reilly asked a federal judge in Alexandria to put him in prison for at least 21 years and 10 months, in part to send a message to others that “the punishment, once you’re caught for this, is so harsh that you don’t even want to consider it.”

U.S. District Judge Leonie M. Brinkema sentenced Douglas to a term not much less than that, saying she was moved by his extensive criminal record. “The pattern is quite stunning,” she said. “I haven’t seen a record this bad in quite some time.”

One of Douglas’s relatives left the court in tears as Brinkema handed down the sentence. Others declined to comment afterward.

Prosecutors are pursuing cases against four other men charged in the same wave of robberies: Bradley Carter, 35; Stephen Powell, 27; Terrence Bell, 25; and Michael Williams, 45. They were all charged last month with delaying commerce by robbery after being linked to various smash-and-grabs by cellphone records, surveillance footage and information that accomplices gave to investigators, according to court filings.

It is unclear what role each of the four men played in the robberies, and they are not all linked to each of the incidents. A man who admitted to being a lookout and scout for the group was sentenced to seven years in prison last month.

Douglas pleaded guilty in August, acknowledging that he organized and sometimes served as a getaway driver for an operation that has been described as sophisticated, lucrative and broad in geographic scope. The robbers often shattered glass displays — as frightened employees looked on — and took items such as watches and handbags bearing upscale labels such as Rolex, Gucci and Michael Kors.

The targeted stores — including a Cartier store on Wisconsin Avenue in Chevy Chase, a Nordstrom at the King of Prussia Mall in Pennsylvania and a Saks Fifth Avenue in Richmond — collectively lost more than $1.25 million in merchandise, prosecutors said.

Reilly said the robbers aroused so much fear among retailers that one store bought a gun and had an employee learn how to use it.

“These victims — these employees and customers — did not know at that time whether their lives were in danger,” Reilly said. “To them, these were life-and-death situations.”

Jessica N. Carmichael, Douglas’s defense attorney, asked the judge to sentence Douglas to no more than 15 years. She said Douglas, the father of three daughters and three stepchildren, was deeply remorseful and intended to enroll in prison job-training programs to begin working toward a productive life.

Douglas, who has worked as a food bagger, driver and substitute teacher, said in court that he wanted to “apologize for what I’ve done.” He wrote in a letter to the court that the prison sentence would be his “last and final incarceration.”

“This is the first time I have felt this way and I am very motivated to move forward with my life,” he wrote. “I am far from perfect and I have made plenty of mistakes in my life but I am not a lost cause.”