Complex sentence: Banks received amnesty in California by then Governor Jerry Brown based on concerns of the nature of the prosecution, refusing to honor the extradition order issued by Janklow, by then governor of South Dakota.
Split into simpler sentences: Banks received amnesty in California from then-Governor Jerry Brown, based on concerns regarding the nature of the prosecution. Brown refused to honor the extradition order issued by Janklow, who was, by then, the governor of South Dakota.