The robbers typically operated in daylight, shattering glass displays at some of the most high-end stores in the D.C. suburbs while frightened employees looked on. They struck as many as 14 times, swiping hundreds of thousands of dollars in watches and handbags from Gucci, Rolex and Michael Kors, according to FBI agents and federal prosecutors.

But after a confidential informant went to police with a tip about two men discussing expensive watches, investigators said that they got the break they needed. FBI agents have arrested two suspects in the spate of smash-and-grab robberies and charged them with delaying commerce by robbery.

In U.S. District Court in Alexandria on Tuesday, a magistrate judge ordered one of them, Walter A. Douglas, 33, held without bond as he awaits another court hearing. Federal prosecutors from the Eastern District of Virginia had argued to keep him locked up, noting his extensive criminal past and saying he was connected to as many as 14 robberies. An FBI affidavit from the case details eight of those robberies.

“He is a danger to the community,” prosecutor Jonathan Fahey said in court.

Defense attorneys had argued for Douglas to be released, saying he is a lifelong D.C. resident who lived with his wife and three stepchildren and posed no imminent danger. Defense attorneys and prosecutors declined to comment after the hearing.

The string of robberies — at least eight of which occurred from December to April — made news around the D.C. region because of where they happened and how they were executed. All of the cases detailed in the FBI affidavit seem to have occurred when the stores were open, and six occurred between 10 a.m. and 2 p.m.

In at least four cases, the robbers shattered displays, according to the affidavit by FBI Special Agent Rachel Taylor Wolford.

Among the robbers’ targets were the Michael Kors store at Tysons Galleria mall, the Gucci boutique in the Bloomingdale’s at Tysons Corner and the Belle­view Jewelers on Belle View Boulevard south of Alexandria, according to the affidavit. The loot was substantial. On March 19 at the Tourneau store in the Pentagon City mall, for example, the robbers took 22 Rolex watches valued at $503,900, according to the affidavit.

Most recently, on April 30, five masked men burst into the Cartier store on Wisconsin Avenue in Chevy Chase, where two of the men fought a security guard as three others smashed open a display case, according to the affidavit. They grabbed 13 watches valued at $131,000 before fleeing. A D.C. police officer who later spotted the getaway car crashed while following it, according to the affidavit.

The officer suffered injuries that were not life-threatening, and the men escaped, police said.

Investigators seem to have first been tipped to Douglas and another man, Floyd T. Davis, 43, when an informant reported having overheard them talk about high-end watches, according to the affidavit. Davis, who is also being held without bond, was arrested early last month and Douglas on Friday, court records show.

According to the affidavit, cellphone records showed Douglas and Davis talking to each other on the days of many of the robberies, and cellphone location data placed one or both of them near several of the crime scenes. Surveillance footage also helped connect them or their cars to several cases, according to the affidavit.

Prosecutors declined to comment on other suspects in the cases.