Prison authorities are denying Chelsea Manning access to the institution’s legal library ahead of a key hearing which may land her in “indefinite” solitary confinement. Human rights groups have called Manning’s treatment torture.

The Army is charging Manning with possession of forbidden items – including a tube of expired toothpaste and reading materials such as the US Senate Torture Report – as well as sweeping crumbs onto the floor of the mess hall. As punishment, the disciplinary board may place her into indefinite solitary confinement. Manning says she has not been allowed to consult the prison’s legal library ahead of the hearing, scheduled for Tuesday.

Prison staff are now denying me access to the law library @ scheduled times--w/only 2 days until my board — Chelsea Manning (@xychelsea) August 16, 2015

Manning was an intelligence analyst who handed over US Army documents about the Iraq and Afghanistan wars to Wikileaks in 2010. Convicted in 2013 on charges of espionage, Manning is currently serving a 35-year prison sentence at the United States Disciplinary Barracks (USDB) in Fort Leavenworth, Kansas.

Born Bradley, Manning announced after the sentencing that he had felt like a woman since childhood and asked to be called Chelsea.

News that Manning might be subjected to extended solitary confinement has alarmed human rights activists. Digital rights group Fight for the Future launched a petition urging the Army to drop the disciplinary charges against Manning. The petition received support from Roots Action, Demand Progress and Code Pink, and by Monday afternoon had over 90,000 signatures. Activists plan to hand the petition to the Army liaison in Congress on Tuesday, ahead of Manning’s disciplinary hearing.

“During the five years she has been incarcerated Chelsea has had to endure horrific and, at times, plainly unconstitutional conditions of confinement,” Manning’s attorney at the American Civil Liberties Union, Chase Strangio, said in a statement. “She now faces the threat of further dehumanization because she allegedly disrespected an officer when requesting an attorney and had in her possession various books and magazines that she used to educate herself and inform her public and political voice.”

Manning posted the documents alleging misconduct on Twitter, showing “sweeping crumbs onto the floor” as one of the purported infractions. She also posted a full list of confiscated reading materials, among which were a Vanity Fair issue with transgender athlete Caitlyn Jenner on the cover, the memoir by Nobel peace prize laureate Malala Yousafzai, and the US Senate Torture Report.

Here are the first four official charging documents from the US Disciplinary Barracks (USDB). More coming soon pic.twitter.com/6Zetual5f2 — Chelsea Manning (@xychelsea) August 13, 2015

This is the official inventory of confiscated books and magazines. pic.twitter.com/MvlaU2UmbL — Chelsea Manning (@xychelsea) August 14, 2015

In a March 2015 article for the Guardian, Manning cited the Senate Torture Report, criticizing what she called the “premeditated and intentional conspiracy to knowingly violate US law, and to avoid any oversight and criminal liability” by the US government and the military. One of the reasons Manning decided to hand over the Army documents to Wikileaks was the realization that by assisting the police of Iraqi Prime Minister al-Maliki, the US was aiding and abetting torture of his political opponents, according to Marcy Wheeler at ExposeFacts.org.

During the trial, the Army infamously kept the whistleblower naked in a cold cell. Manning’s supporters say the threat of solitary and the current disciplinary charges amount to torture, and is a kind of vindictiveness and retaliation for Manning’s outspoken criticism of US policies.

Declaring Chelsea Manning’s Voice against Torture Contraband https://t.co/SxPFxOCYsQ — emptywheel (@emptywheel) August 17, 2015

“Chelsea is facing serious repercussions and punishment if these charges are upheld, yet the prison has denied her the right to legal counsel, even legal counsel at her own expense,” said Nancy Hollander, one of Manning’s attorneys. “Now we have learned the prison authorities have denied her the use of the prison library to prepare for her hearing. The whole system is rigged against her. She cannot have a lawyer to assist her; she cannot prepare her own defense; and the hearing will be secret. This harassment and abuse must end.”

The documents Manning handed over to Wikileaks included videos of US airstrikes that killed civilians in Iraq and Afghanistan, 250,000 US diplomatic cables, and 500,000 Army reports that became known as the “Iraq war logs” and “Afghan war logs.” She will be eligible for parole in seven years.