Khthon documents mass graves, atrocity crimes, and forensic evidence from conflict zones worldwide. Our work is strictly humanitarian and apolitical.
This site may contain imagery and descriptions of deceased individuals, violent injuries, and human remains gathered in the course of active investigations. Content is presented for accountability and documentation purposes only.
Khthon documents mass graves, atrocity crimes, and forensic evidence from conflict zones worldwide. Our work is strictly humanitarian and apolitical.
This site may contain imagery and descriptions of deceased individuals, violent injuries, and human remains gathered in the course of active investigations.
Country / Region Overview
Cambodia's modern history is inseparable from the trauma of the Khmer Rouge — one of the most intensive genocides of the twentieth century, carried out in less than four years.
After years of civil war, the ultra-Maoist Khmer Rouge seized power in 1975 under Pol Pot and set out to remake society through radical agrarian collectivism. Cities were emptied, money and religion abolished, and communities forced into labour camps. Anyone suspected of disloyalty — intellectuals, ethnic minorities, Buddhist monks — was targeted for execution. Between 1975 and 1979, an estimated 1.7 to 2 million people — nearly a quarter of the population — perished from starvation, disease, and systematic killings. The regime collapsed when Vietnam invaded in late 1978, but by then the country had become a graveyard of its own citizens.
"Today, Khthon's work ensures that Cambodia's hidden landscapes of atrocity remain visible to history."
— Khthon Field Assessment
The mass graves of Cambodia — collectively known as the Killing Fields — are scattered across the countryside. Sites like Choeung Ek outside Phnom Penh are among the most documented, but thousands of burial pits remain unexcavated. These graves are distinctive: shallow, massed together, often accompanied by execution centres such as the infamous S-21 prison. Many are overgrown, eroded, or integrated into farmland, while others lie in politically sensitive zones. Investigations led by the Extraordinary Chambers in the Courts of Cambodia (ECCC) and the Documentation Center of Cambodia have provided detailed records, but forensic analysis has been partial and inconsistent.
For Khthon, Cambodia represents one of the rare contexts where mass graves are both numerous and historically mapped, allowing for clear geospatial confirmation. Our work builds on this foundation by re-examining the geography of execution and burial sites, situating them within patterns of forced relocation and camp systems, and updating archival data with satellite and social-media intelligence to ensure the country's atrocity landscapes remain visible to history.
1970–1975
Civil war and U.S. bombing
Following the U.S.-backed coup against Prince Sihanouk, Cambodia descends into civil war. U.S. bombing campaigns kill tens of thousands of civilians and destabilise rural areas, accelerating Khmer Rouge recruitment. The Khmer Rouge seize Phnom Penh on April 17, 1975.
1975
Year Zero — forced evacuation of cities
The Khmer Rouge declare "Year Zero" and forcibly evacuate Phnom Penh and all major cities within days, driving millions into agricultural labour camps. Money, private property, and religion are abolished. Targeted killings of former officials, military officers, and educated Cambodians begin immediately.
1975–1979
Systematic killings — S-21 and the Killing Fields
Tuol Sleng (S-21) functions as a Khmer Rouge security prison in Phnom Penh. At least 17,000 people are documented as passing through — virtually all executed. Victims are transported to Choeung Ek and other sites, forced to dig their own graves. Mass pits contain bodies stacked in layers, with evidence of execution by blunt force, bladed weapons, and chemical agents.
1979
Vietnamese invasion — regime falls
Vietnamese forces enter Cambodia in December 1978 and capture Phnom Penh in January 1979, ending Khmer Rouge rule. Survivors begin returning to cities. Investigators enter S-21 and discover the execution record. Thousands of mass grave sites across the countryside begin to be identified, though systematic documentation takes decades.
1994
Documentation Center of Cambodia founded
DC-Cam is established to collect, preserve, and translate records of the Khmer Rouge regime. Over decades it compiles testimonies, maps of mass grave locations, and confessions from S-21. Its database of over 20,000 grave sites becomes the primary reference for Cambodian forensic geography.
2006
ECCC established
The Extraordinary Chambers in the Courts of Cambodia — a hybrid UN/Cambodian tribunal — begins operations. Trials of senior Khmer Rouge leaders produce detailed records of crimes, including evidence from mass grave exhumations. Nuon Chea and Khieu Samphan are ultimately convicted of genocide in 2018.
2018
Genocide convictions — Nuon Chea and Khieu Samphan
The ECCC Trial Chamber issues its final judgment, convicting Nuon Chea (Pol Pot's deputy) and Khieu Samphan (former head of state) of genocide, crimes against humanity, and grave breaches of the Geneva Conventions. The verdicts anchor Cambodia's judicial record of atrocity, though most perpetrators died without prosecution.
Ongoing
Khthon monitoring — archival and satellite integration
Khthon re-examines the geography of execution and burial sites using DC-Cam archival data cross-referenced with multi-temporal satellite imagery. Many sites documented in the 1990s have undergone significant land-use change. Khthon's methodology focuses on detecting terrain anomalies in agricultural and forested areas and updating the spatial record with current imagery and community confirmation.
Browse Khthon's full catalogue of country and case reports across seven global regions, or get involved with our ongoing investigations.
