This Ramadan, Syrian families across the country and around the world will be breaking their fast in the absence of a loved one.
As favorite delicacies are prepared and relatives gather, the empty chair at the table will be a painful reminder of those who are absent but never forgotten. Many will experience the ongoing pain and torment of having no news as to where their relative is being held, or if they are alive or dead.
A recent report by the Syrian Network for Human Rights (SNHR) estimates that the number of detainees is likely to exceed 215,000. Ninety-nine percent of these have been detained by regime forces. Last month alone, SNHR documented 577 cases of arbitrary arrest, of which 423 were arrested by regime forces, including 44 children and 88 adult women.
Most of these were civilians arrested in areas under regime control. Those detained include activists and the family members of armed opposition fighters. They also include many men in the 18-42 year age group who have been arrested for conscription purposes and will likely be sent to the front lines to fight.
The inhumane conditions in regime detention facilities have been widely documented by local and international human rights organisations and corroborated by the harrowing testimony of those who have been released.
Prisons are overcrowded and unsanitary. Detainees are given inadequate food - are sometimes purposefully starved - and suffer from medical neglect. Torture is practiced on an industrial scale. Women, and men, have suffered rape and sexual abuse.
In February, Amnesty International released a report accusing the regime of the crime of extermination. The report estimates that 13,000 people were executed in Saydnaya military prison near Damascus, with mass hangings occurring on a weekly basis.
In January 2014, 'Caesar', a defector who had worked as a military police photographer responsible for recording deaths in regime custody between 2011 and 2013 released 55,000 photos of corpses to human rights investigators. They provide evidence of the killing of 11,000 detainees, despite only covering one part of the country.
The detainees are not only Muslims. Opposition activists from other groups - Alawites and Christians - also languish in Assad's dungeons.
Arbitrary arrests have also been performed by other authoritarian groups empowered by the chaos of the conflict. In May the SNHR documented the arrest of 62 individuals by Islamic State group (IS), including five children and two women. IS targets civilians who violate its rules as well as those who try to flee its areas to those controlled by opposition groups.
Armed opposition factions were responsible for the arrest of 45 people, including three children, medical personnel, media activists and fighters from other opposition factions. The latter category has swollen as a result of recent infighting in the Damascus suburbs.
As the PYD continues its crackdown on Kurdish opposition groups and media activists, meanwhile, in addition to its arrest campaigns for the purpose of conscription, the PYD-dominated Rojava Autonomous Administration arrested 36 people, including three children and five women.
Little progress on the fate of detainees has been made in international negotiations, despite the central importance of this issue for Syrians. Access for international monitors to inspect detention facilities has not been granted. Regime promises have been broken time and again, causing bitterness and disappointment for the families of prisoners.
In April, protests were held in Idlib over the failure of the regime to release 1,500 prisoners as agreed in the evacuation deal for the long-besieged Damascus suburb towns of Zabadani and Madaya. In the final deal for the forced displacement of the residents of Al Waer in Homs, the condition relating to the release of detainees was dropped. The residents of Al Waer had been demanding the release of more than 7,000 detainees for two years in exchange for leaving their homes for an uncertain and precarious future.
Their frustration that the prisoner release was not fulfilled is directed not only at the regime, but also at those who negotiated on their behalf.
Many Syrians have not spoken publicly regarding the arrest of family members for fear of retaliation. But others have refused to be silenced. Families for Freedom is a Syrian-led campaign tirelessly advocating for the release of those arbitrarily detained or forcibly disappeared by all parties to the conflict, regardless of the political affiliation of the prisoner.
They have organised protests in solidarity with detainees and campaigned to keep the issue on the political agenda, particularly during international negotiations.
A statement released during the Astana talks read: "We refuse to place the fate of our loved ones in the hands of armed men… We do not accept prisoner exchanges arranged between military sides as a replacement to the horror of mass detention in Syria… Our civilians will be forgotten."
Among the Families for Freedom demands is the release of a list of names of detainees, an immediate end to the practice of torture, access to detention facilities for humanitarian and human rights organisations, and the abolition of exceptional courts, particularly the counter-terrorism court which is used to detain opposition activists in the absence of fair trials.
Syria's prisons are filled with those who rose up peacefully to call for freedom, democracy and social justice. They are full of teachers, medical and humanitarian workers. They are full of Syria's heroes. When people ask you "where are the moderates?" please remind them: Thousands are lost in the Syrian gulag.