You may have heard of civil asset forfeiture.
That's where police can seize your property and cash without first proving you committed a crime; without a warrant and without arresting you, as long as they suspect that your property is somehow tied to a crime.
Now, the Oklahoma Highway Patrol has a device that also allows them to seize money in your bank account or on prepaid cards.
http://www.news9.com/story/32168555/ohp-uses-new-device-to-seize-money-used-during-the-commission-of-a-crime [news9.com]