This section contains spoilers for: Dragon Age: Origins.
If the Warden attempts to enter Brother Genitivi's study, Weylon will try to stop them. The only way to get past is by killing him. Upon entering the study the Warden will find a corpse described as "the real Weylon," as well as some of Genitivi's research notes pointing to the Village of Haven. Depending on the Warden's actions during the The Urn of Sacred Ashes, Brother Genitivi himself may return to the house once the quest has been completed. If the Warden visits him after he returns home, he will provide a gift.
Bug! A glitch may cause Genitivi's home to continue to have an active quest marker on it, even after the impostor Weylon has been killed and the research journal found. The impostor's body will also remain in the building in this case, with sparkles to indicate that it may be looted, even if it has already been.