WASHINGTON – Police are investigating three armed robberies that occurred Sunday in Northwest D.C.

The first happened about 1 p.m. in the 3100 block of M Street in Georgetown. Channel 9 reports that Serendipity 3 restaurant workers were on a cigarette break in an alley when they were robbed at gunpoint.

A second armed robbery happened an hour later on Embassy Row in the 1900 block of 23rd Street.

The victims of both incidents described similar suspects—three young black males in blue or green T-shirts.

A third robbery was reported late Sunday night at the Five Guys restaurant on Wisconsin Avenue.

Police say they are investigating whether the robberies are related.

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