Tens of thousands of political prisoners are being held without charge or on confessions obtained through torture.

For the crime of providing food to displaced Aleppans, her friends say, activist Zilal Salhani became one among tens of thousands of political prisoners left to an uncertain fate in Syria’s jails.

Arrested at 19 by regime forces in Aleppo in July 2012, Salhani has now spent her university years in a series of shadowy government detention centres. She was convicted of supporting “terrorists”, but according to friend Mohammad Shbeeb, Salhani was always peaceful.

Before her detention, the Free Syrian Army had recently taken certain areas in and around Aleppo, prompting retaliatory government air strikes. Salhani, an engineering student who had been an active participant in civil demonstrations against the government of President Bashar al-Assad, took food to those displaced by the heavy fighting and helped them to find shelter, Shbeeb said.

SPECIAL SERIES: The disappeared of Syria

According to Human Rights Watch, tens of thousands political prisoners are being held in Syrian jails, many without charge. Other activists have been convicted on unsubstantiated evidence or confessions obtained through torture.

Families are kept in the dark about the fate of their loved ones, causing rumours to swirl.

Noor, a former prisoner who was held in the same cell as Salhani in the overcrowded Adra prison outside Damascus for eight months before her release earlier this year, said conditions in the jail were unspeakable.

“I cannot describe the injustices we faced in Adra,” Noor, who declined to give her last name, told Al Jazeera.

Noor, who now lives in neighbouring Turkey, was also held on “terrorism” charges after distributing food to displaced Syrians and handing out pamphlets in support of the country’s civil uprising.

“Civilian activists who took to the street at the beginning of the revolution were considered by the regime as very dangerous people, because they were against using weapons and tried to keep the resistance peaceful despite the regime trying to militarise it,” said Kareem Hourani, a member of the Detainees Voice activist group.

Noor said that Salhani’s arrest had a significant effect on other activists.

“Zilal was one of the first detainees in Aleppo, and other people joined demonstrations because of her arrest, so they are making an example of her,” she said. “For us, it was a very big loss when she was arrested. We were so disappointed. She was so strong.”

READ MORE: You probably won’t read this piece about Syria

Amid the appalling conditions in prison, Salhani’s health had been suffering, Noor said. Breakfast, served at 10am, consisted of a slice of bread and either a segment of cheese or some jam, and the only other meal for the day, served at 6pm, was rice or bulgur with a potato or a tomato and a slice of bread.

When the prison guards initially asked her to remove her niqab, Salhani refused, said Shbeeb, citing information from other prisoners. “It’s bad for anyone to enter the prison, but it is even worse for girls. They looked at her like an animal looking at his prey.”

Shbeeb was himself arrested for attending a demonstration in 2011 and held for seven hours, during which time he was beaten and tortured.

Significant prisoner exchanges have been few and far between in Syria, but could hold the key to any political transition.

The Red Cross is the only agency with access to government-run detention facilities, and officials made several visits to prisons last year, according to Robert Mardini, the Middle East director for the International Committee of the Red Cross. The organisation declined to provide details of its confidential findings.

“A lot of our friends are still in prison. Some of them have been killed there,” Shbeeb said.

Noor said that her conversations with Salhani focused on their fate in prison, and on the disappearance each week of three to six women from their block – although such “political” discussions were banned inside Adra, punishable by beatings.

More than 65,000 Syrians have been forcibly “disappeared” since the beginning of the civil war in March 2011, according to Amnesty International.

INTERACTIVE: Life on hold

In an effort to silence dissenting voices, the Syrian regime has painted the entire opposition as “terrorists”, despite the pacifistic beliefs held by many activists. Yahya Shurbaji, known as “the man with the roses” because he met soldiers with flowers in the initial days of the uprising in Daraya, has been in jail since September 2011. Another Daraya activist arrested with him has since died in prison.

“I can mention many names … who adopted the methodology of responding to violence by distributing flowers and water to Assad’s soldiers,” Hourani said. “The regime was afraid of them because they were refuting its claims of fighting terrorists and armed people.”

Syria’s policy of political imprisonment long predates the civil war. In one case from 2009, blogger Tal al-Mallohi was arrested at 18 for her online writings, held without charge for years, and ultimately sentenced in 2011 to five years in prison for “spying”.

There have also been rare rays of light, including the release last year of prominent human rights defender Mazen Darwish, who had been held for three years in government jails. Hourani believes that his release was made possible through international pressure.

“[The international community] stood up for their justified cause, confronted the regime and demanded a cease to its farcical trials of activists,” Hourani said. “That concrete pressure is missing in the cases of the other detainees.”