What factors are considered in determining whether a defendant has a history of similar crimes?

This court looks to several factors to determine whether prior offenses were part of a "common scheme or plan": (1) whether the crimes were committed within a short period of time; (2) whether the crimes involved the same victim; (3) whether the defendant was arrested by the same law enforcement agency for both crimes; and (4) when the arrests occurred and whether both crimes were solved during the course of one investigation. United States v. Chapnick, 963 F.2d 224, 226 (9th Cir.1992). The court also examines the similarities in the offenses. Id.