Buying a ski mask isn’t illegal, but could restricting their sale help prevent crime? The notion is stirring debate among some Northwest Washington residents after reports of robberies committed by men wearing ski masks. The frequency of the robberies also has caught attention of police, who say one neighborhood crew is frequently purchasing masks at a local sports store for the express purpose of committing robberies. “They clearly are a problem. Otherwise, we wouldn’t see it being mentioned in all the reports,” said Faith Wheeler, an Advisory Neighborhood Commission member from the Takoma neighborhood in Northwest. And while police from...