A leaked 400-page document released by the New York Times reveal new details about how the Chinese have organised the mass detention of more than 1 million people from its Muslim minorities, including the Uyghurs and Kazakhs.
The exclusive report, described by the Times as the "one of the most significant leaks of government papers from inside China", exposes the key role played by top Chinese officials as well as President Xi Jinping in the establishment of the indoctrination camps.
According to the New York Times, the whistleblower was an anonymous member of the Chinese political establishment, who wanted to ensure top Communist Party leaders could not escape culpability for the crackdown.
The United Nations has said there are credible reports at least 1 million Uyghurs are detained in Xinjiang's "re-education" camps.
China maintains its treatment of Uyghurs — a Turkic-speaking Muslim minority — is necessary to counter terrorism and extremism.
The leaked papers reportedly reveal President Xi laid the foundation of the crackdown in 2014 in private speeches to officials, after a deadly knife attack at a train station by Uyghur militants in which more than 130 people were injured and at least 33 were killed.
However, it does not show Mr Xi directly ordering the creation of the detention camps.
In his speeches, Mr Xi called for an all-out "struggle against terrorism, infiltration and separatism" using the "organs of dictatorship" and showing "absolutely no mercy".
The documents shows a sharp difference between Mr Xi and his predecessor Hu Jintao's beliefs on the appropriate way to control terrorism in the sensitive region, which borders Pakistan and Afghanistan.
While Mr Hu responded to the deadly 2009 riots in Xinjiang's capital Urumqi with a clampdown, he also pushed for economic reforms. However, Mr Xi said despite economic growth, "ethnic separatism" and "terrorist violence" was still on the rise.
"The psychological impact of extremist religious thought on people must never be underestimated," Mr Xi told officials on his trip to Xinjiang in 2014.
"People who are captured by religious extremism — male or female, old or young — have their consciences destroyed, lose their humanity, and murder without blinking an eye."
According to The New York Times, the documents show the camps grew in August 2016 after a new party boss, Chen Quanguo, was appointed to the region. He used Mr Xi's speeches to justify the campaign and told officials to "round up everyone who should be rounded up".
But the Government anticipated "turmoil" at tearing families apart, with the documents giving detailed instructions to local authorities on how to handle students who might return home to find their parents, relatives and neighbours gone.
The students were told while their family member had committed no crime, they could not be released, the Times reported. However, the students' behaviour could either shorten or extend the detention of their relatives.
The documents also reportedly show there was resistance to the crackdown in the party, with some fears that the detention would further inflame separatism.