Plaintiffs Mitchell Katz and Hasan Aksu sued Stephen Tanabe of the Contra Costa County Sheriff’s Office for helping private investigator Christopher Butler set up a “dirty DUI” sting of which they were both victims. The United States District Court for the Northern District of California held that Tanabe did not violate the Fourth Amendment in stopping the plaintiffs because they were in fact driving while intoxicated.
Tanabe and Butler met while they were both working as police officers for the Antioch Police Department in the mid-1990s. Tanabe left for the Danville Police Department in Contra Costa County, and Butler left to start his own private investigation firm. In October 2010, Butler and Tanabe agreed to participate in a dirty DUI scheme to catch plaintiffs with DUIs to use against them in Butler’s clients’ cases in family court. According to the court, Butler agreed to pay Tanabe for his help with cash, cocaine, and a Glock firearm.