Authorities: Journalists harassed at pipeline encampment

North Dakota authorities are investigating a confrontation between journalists and protesters of the four-state Dakota Access oil pipeline.

The Morton County Sheriff's Department said Wednesday that filmmaker Phelim Mcaleer and two colleagues were in the protest camp Tuesday near the Standing Rock Sioux reservation when people they were interviewing "got offended by a line of questioning." Mcaleer made the documentary "FrackNation," a 2013 rebuttal of anti-fracking film "Gasland," about the process of shooting liquid under high pressure below ground to free energy from rock.

One person grabbed a reporter's microphone, dragging him several feet, and the journalists' car was blocked from leaving until law enforcement arrived.

The camp is home to protests against Energy Transfer Partners' $3.8 billion pipeline. Demonstrators believe the pipeline threatens sacred sites and the Missouri River.