I would imagine an act is not a crime till it is investigated by investigators or tried in court. Everything you hear now a days is "allegedly" because no one wants to be definitive and then get sued for libel in the chance they are wrong.

Perfect example. Nicholas Cruz ..just googling and picking an article.

"Cruz is accused of gunning down students and teachers in various classrooms at the school in Parkland on February 14, in one of the deadliest mass shootings in modern US history."

Why is he accused? We all know he did it. Why not say "Cruz gunned down..."? This is after he confessed to it, after security footage was reviewed.