Associated Press stories are written with all kinds of extras thrown in so that each organization can determine what it wants to keep. If you’re a big national paper, you might retain the imperial-to-metric conversions, the dollar-to-euro conversions, the pronunciations of exotic surnames, etc. If you’re a tiny paper, you might strip all that out. So, why put in “kilometers (miles)” when there’s no number to convert? I think it’s so that if you are going to strip out all of the references to kilometers, you’ll remember to do it there, too. Otherwise, you’ll have a story with X miles here, X miles there, and one totally random reference to kilometers that got left in because the editor skimmed over it by accident.