After a robbery in the Foggy Bottom area of Northwest Washington late Sunday, the police said they were looking for a man wearing a mask. A hospital mask.

The robbery was of the grab-and-run type and occurred about 11:30 p.m. in the 2500 block of Pennsylvania Avenue NW, according to D.C. police.

No injury was reported. But, the description of the mask helped make the robbery just the sort of crime that might stir the public’s imagination.

A hospital mask, the victim told police. A blue hospital mask. Did that mean anything.? Is that what robbers wear?

In available accounts, few robbers are described as wearing hospital masks. Ski masks yes. Halloween masks, perhaps. Hospital masks, no. Or unlikely. Could that be a clue?

The flu epidemic has appeared to be abating. But flu is still widespread. Was the robber a flu victim who was reluctant to spread germs?

But careful analysis might suggest that anyone so concerned about the welfare of others would not be led to criminal acts. So, how is an investigator to proceed?

Well, the description was detailed. The mask was only one of a number of details.

The other parts of the description: The robber was black. He was male, and about 6 feet 1 to 6 feet 3 inches tall. He wore a coat, a long black coat that appeared to have fur trim.

He was in sweatpants, gray sweatpants. His boots were black. According to the description, the robber carried a white plastic bag.

Exactly what was taken could not be learned immediately.