The FBI is investigating political activists campaigning against the Dakota Access pipeline, diverting agents charged with preventing terrorist attacks to instead focus their attention on indigenous activists and environmentalists. Officers within the FBI's joint terrorism taskforce have attempted to contact at least three people tied to the Standing Rock water protector" movement in North Dakota. "The idea that the government would attempt to construe this indigenous-led non-violent movement into some kind of domestic terrorism investigation is unfathomable to me," said Lauren Regan, a civil rights attorney. "It's outrageous, it's unwarranted and it's unconstitutional." Regan ... said she learned of three cases in which officers with the taskforce, known as the JTTF, tried to talk to activists in person. She described the encounters as attempted "knocks and talks", meaning law enforcement showed up at people's doors without a subpoena or warrant and tried to get them to voluntarily cooperate with an interview. The three individuals ... asserted their fifth amendment rights and did not respond to the officers, according to Regan. All three contacts were made in recent weeks after Trump's inauguration. Trump, a former investor in Energy Transfer Partners, the Texas-based firm behind the pipeline, took executive action in his first week in office to expedite the project. On Wednesday, workers began drilling to complete the pipeline.