Laura Poitras gained notoriety as the documentary filmmaker behind the 2014 Oscar-winning movie Citizenfour, a film about the time she and Glenn Greenwald spent with NSA whistleblower Edward Snowden.

What's less known about Poitras is that from 2006 until 2012, she was stopped at the US border every single time she entered the country. In all, she was stopped on more than 50 occasions. Poitras, who is a US citizen, never got a satisfactory explanation as to why the detentions took place.

Frustrated after years of stonewalling, today Poitras said she's working with lawyers at the Electronic Frontier Foundation to get answers. The group is filing a Freedom of Information Act (FOIA) lawsuit against the Department of Justice and two other agencies.

Poitras said she's filing the suit to support less high-profile people who were subject to the same years of "Kafkaesque harassment" that she was.

"This simply should not be tolerated in a democracy," she said. "We have a right to know how this system works and why we are targeted."

It seems likely that Poitras' treatment had something to do with the provocative movies she had made. Before Citizenfour, Poitras made the 2006 movie My Country, My Country about an Iraqi doctor who spoke out against the US occupation. She also put together a 2010 movie about Guantanamo prison and the interrogation of Osama bin Laden's former bodyguard.

"The government used its power to detain people at airports, in the name of national security, to target a journalist whose work has focused on the effects of the US war on terror," said David Sobel, EFF senior counsel.

The detentions only stopped after Poitras spoke out about them in 2012. Greenwald, who wrote a popular column for Salon at that time, penned a story highlighting her treatment at the border, and a group of documentarians petitioned the government on her behalf.

During her detentions, Poitras was falsely told she had a criminal record, that she appeared on a "security threat" database, and that she was on the government No-Fly list. Her laptop, camera, phone, and notebooks were seized and copied.

Poitras filed FOIA requests last year seeking answers about her six years of detentions but got little response, leading to this suit. The FBI ignored her request for a year, then in May said it had six pages of relevant documents. However, the FBI was withholding all six pages due to grand jury secrecy rules, the EFF said.