I believe that it could be assumption based. That ER assumed the items were packed in his bag, and that since MR said the bag was gone, so where those items, if she believed he packed them. The fact that we don't seem to know the contents of the bag, tells me that ER may not have had known exactly what Dylan packed either. That could be why we don't have a "contents list" for what was in the backpack.
Thank You , but then by now the chargers would of been found at Dylan's home , no ? and we have never heard anything different than Dylan had the iPod and Mobile phone charger on him.