In Documentaries About Criminals Of This Period, ...
... it's constantly emphasized that a favorite trick of B&C and fellow delinquents to avoid capture was to cross state borders because the authorities of one state had no jurisdiction in other states, and therefore had no legal authority to arrest the crooks that had committed crimes in their jurisdiction.
Why did police of that time suffer that constraint that so obviously sabotaged their effectiveness? When and how was it removed?
God is subtle, but He is not malicious. (Albert Einstein)