(CNN) Police in Grand Rapids, Michigan, are investigating after anti-Semitic posters were discovered on the door of a synagogue on Sunday.

Temple Emanuel Rabbi Michael Schadick arrived Sunday morning around 8 a.m. and found some disturbing posters . One had a picture of Hitler with the words "Did you forget about me?" The other read, "A crusade against Semite led subhumans."

The posters were credited to the Vorherrschaft Division, an extremist neo-Nazi group.

No arrests have been made so far and there are currently no definitive leads, Sgt. John Wittkowski with the Grand Rapids Police Department told CNN. The investigation is being handled by the major crimes detective unit.

Wittkowski said that the incident is believed to have happened between 8 p.m. on Saturday and 8 a.m. on Sunday. He said the synagogue was in a "relatively quiet" residential neighborhood.

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