There’ve been NO arrests after a booby-trapped bomb exploded on a Des Moines bike trail Tuesday, injuring a passing biker who set it off by hitting a trip-wire. Police spokesman Lieutenant Kelly Willis says the police response was thorough.Lt. Willis says 44-year-old Wanda Harvey of Des Moines was hit in the leg by flying nails from the bomb. He says her injuries are not severe. Willis says security has been stepped up, though he’s not expecting a repeat bombing.Willis says by strict definition, this is NOT considered an act of terrorism, so there’ll be no federal involvement in the case.Willis says Harvey had been riding downhill fast when she hit the trip wire so he thinks a walker would’ve been more badly hurt.