If it is a newspaper it's most likely on of those, those four are the only newspapers in Iceland that come out every day.
I doubt it is Sport.is, the website you linked to, seeing as they get most of their football related stories from fotbolti.net, the biggest football website in Iceland.
I think there is a good chance this guy is telling the truth. Iceland is a very small country and we don't have that many football journalists. Those we do have tend to have very good connections to players, agents etc.