At approximately 8:20 am, a report was received that protesters were hanging anti-pipeline banners from overpasses in Bismarck. The Bismarck Police Department responded and located 4 of the protesters involved in this activity. Two of the protesters were arrested for drug violations and an outstanding warrant.At approximately 4:40 pm, the semi-tractor that has been on the Backwater Bridge in the past 2 days returned to the bridge along with approximately 50 persons. The semi-tractor and persons eventually left the bridge which was all cleared by 6:00 pm. No problems were encountered with this group.