Authorities drop 33 cases against Dakota Access protesters

Prosecutors struggled to prove those charges before Judge Allan Schmalenberger, who ruled in multiple cases that the Morton County State's Attorney office had failed to meet its burden of proving that protesters were given proper notice that they were on private land, either with signs or verbal warnings.

Demonstrators staged months of protests near the Standing Rock Reservation in North Dakota to try to stop the $3.8 billion, four-state pipeline, saying it will pollute water and damage Native American sacred sites.

According to the joint information center, 761 arrests were made during the protests.