The day before D.C. police say four siblings robbed a bank in Washington’s Mount Vernon Square, authorities allege the same group held up a gas station in Silver Spring at gunpoint.

Police said the robberies occurred May 14 in Maryland and May 15 in the District — and are unusual in that three brothers and a sister are accused of colluding in an alleged family criminal enterprise.

The suspects’ family members could not be reached Friday, and attorneys for all four defendants declined to comment. Three suspects were ordered detained during a hearing Friday in U.S. District Court; the fourth was ordered detained Thursday.

Police identified the siblings as: Allante Alexander, 20; Alex Alexander, 20; and Alvin Alexander III, 24, all of Southeast Washington, and Allesha Alexander, 25, of Northeast Washington. The brothers are charged in federal court and in Montgomery County with bank robbery. Their sister is charged in both cases as an accessory.

Montgomery County police said the foursome was charged in the May 14 robbery of an Exxon gas station in the 8300 block of Colesville Road, next to the Silver Spring Metro station. It occurred about 3 a.m., and police said a clerk was confronted at gunpoint.

Allesha Alexander (Montgomery County Police)

Then, at about 10:40 a.m. on May 15, authorities said, three men walked into the Colombo Bank in the 1300 block of Ninth Street NW. Court documents say clerks recognized them because they had been lingering inside the bank days earlier, and the clerks grew suspicious because the men were wearing winter clothes on a warm day.

Documents filed in federal court say one man handed a teller a note and placed a black backpack on the counter. Another man “reached into his waistband as if he was reaching for a weapon,” the documents say, though no gun was displayed. The note said: “Empty Drawer Fast or Everybody Dies!!!” The documents say the teller put $800 in the bag, along with a dye pack that is designed to explode and mark stolen money.

Authorities said in the documents that the red dye pack exploded in the bag, which was abandoned next to a red compact Chevrolet that was at a gas pump at a station across the street from the bank and, according to police, was used as the getaway vehicle. The documents say that inside the bag police found $780 of the $800 taken in the robbery.

Jennifer Jenkins and Lynh Bui contributed to his report.

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