WASHINGTON, D.C. ? U.S. Park Police have charged five people in a string of violent attacks on tourists near national landmarks, authorities said Friday, crimes that prompted police in the nation’s capital to declare a citywide crime emergency.

The suspects, who were arrested over the past two weeks, are accused of taking part in five different attacks on three nights in May and July. Authorities said they stole cell phones, cash, credit cards and other items from victims, and a 17-year-old girl said she was raped during a robbery in a dark corner of the National Mall.

Working in groups of two or three, officials said the suspects chose dark spots at night on the heavily visited Mall, a broad expanse of grass and trees that stretches from the U.S. Capitol to the Lincoln Memorial, bordered by museums with the Washington Monument in the middle.

Wielding a gun, they forced their victims, including a family with two children, to the ground before robbing them, authorities said. In several cases, women were groped, according to charging documents filed in D.C. Superior Court.