Washington, D.C. ? Liz Johnson showed up Friday to the U.S. Holocaust Memorial Museum with 12 Girl Scouts in tow. None of them was alive when the Holocaust took place, but they were determined that a fatal shooting at the museum two days earlier wouldn’t keep them from supporting its mission.

The members of the Dallas troop were among the hundreds of visitors who streamed into the museum as it opened for the first time since authorities said 88-year-old James von Brunn of Annapolis, Md. gunned down a security guard who had opened the door for him.

The museum, which was closed Thursday for a day of mourning, opened to crowds that officials said were about the same size as usual this time of year.