In a chapter entitled 'The Ban and the Wolf', Agamben traces the Germanic, Anglo-Saxon (but also Latin in the form of the homo sacer) origins of the wolf-man or werewolf to the figure of the bandit who, being banned by the community, quidlibet possit eum offendere, 'may be harmed by anyone'.
[Indeed Agamben's argument places the ban, and the abandonment it entails, at the archeo-logical - in the sense of foundational, ἀρχή in Greek meaning beginning - heart of political sovereign power, which is essentially a form of power of life and death, vitae necisque potestas, not unlike the one that was held by the Roman patriarch over his sons or the totalitarian tyrant over his nation's population.]
The banned bandit that anyone may kill with impunity was said to have a 'wolf's head' - as per the laws of Edward the Confessor in 1030-1035 which use the term wulfesheud - thereby assimilating him to the hybrid figure of the werewolf who, in combining beast and man, φύσις (nature) and νόμος (custom), city and forest (both featured in the movie)
"dwells paradoxically within both while belonging to neither."
If one considers and takes seriously the allusion in the film to the main character being Jewish and his (nighmared) execution by Nazi monsters - note the menorahs in the background of that scene - then this werewolf/bandit angle gains in political moment, if one perceives the film as offering a covert commentary on the Jewish condition, the Jews traditionally having been only liminally included in - and therefore partly excluded from - the societies they were circumstantially forced to assimilate to.
[It is regrettable that the usually genial Rob Ager failed to give proper focus to this aspect of the movie in his analysis of it, instead of a brief and somewhat feeble allusion to it.]
The Jewish-werewolf connection of the film is particularly serendipitous as regards Agamben's book because Jews did - historically and juridically - come to form an excluded, nationally (our word 'nation' coming from the Latin for birth, natio, and to be born, nascere) abandoned group that were able to be killed with impunity by the Nazi regime, just as the werewolf historically was no more than a shunned bandit who could be killed by anyone without that killing amounting to homicide or criminal murder - the Nuremberg Trials testifying to that fact on the basis that they had to invent the category of 'crime against humanity' to successfully prosecute the Nazi architects and enforcers of the Final Solution.
Viewers of the film know that David (note the Jewish name), the American Werewolf in London himself, is pursued and killed at the end of the feature by an urban mob and indeed there are also hints very early on in the film, as David and his friend Jack visit a country pub, that their 'sort' is not welcomed by English rural villagers either - whether as Americans, foreigners or, indeed, Jews.
Addendum - Of course, Agamben's book makes the wider point that, at bottom, we are all werewolves (note Thomas Hobbes' famous observation according to which homo homini lupus est, man is a wolf for man), not just Jews, in so far as we are all operating under a foundational ban that grounds the modern Nation State and its taking control of our bare, naked lives as part of an argued biopolitical (βίος, life) or, in the worst case scenario, thanatopolitical (θάνατος, death) paradigm of sovereign power.