After the withdrawal of regular Confederate troops in the fall of 1861, a bitter guerrilla conflict soon began between bands of pro-Confederate irregulars (commonly known as bushwhackers) and the Union homeguards. By early 1863, Frank, ignoring his parole and oath of allegiance, had joined the guerrilla band of Fernando Scott, a former saddler. He soon switched to the more active command led by William Clarke Quantrill.
