CNET’s expert staff reviews and rates dozens of new products and services each month, building on more than a quarter century of expertise.

Dazio reported from Berlin. Geir Moulson in Berlin, and Kwiyeon Ha in London, contributed to this report.

Andreas Sundling, 28, was among those forced to barricade themselves inside the school. “We heard three bangs and loud screams,” he told Expressen newspaper while sheltering in a classroom. Geir ...