HUMBOLDT, Iowa (AP) -- A northern Iowa sheriff says a man hacked away at his fingers in a desperate bid to free his trapped hand from beneath a vehicle. The Des Moines Register reports (http://dmreg.co/18Occfy ) that Michael Bohan got a flat tire Tuesday while on his rural Humboldt mail route and planned to take care of it the next day. His brother-in-law Dave Holst spotted Bohan's vehicle Wednesday and soon saw that the vehicle had fallen off jacks and that Bohan was trapped, his left hand stuck in a wheel mechanism. Rescue crews were called, and they freed Bohan. Humboldt County Sheriff Dean Kruger confirmed that Bohan had been using a pocketknife to cut off fingers so he could get free. Bohan says he's not sure whether any of Bohan's fingers were completely severed. ___ Information from: The Des Moines Register, http://www.desmoinesregister.com