A British forensic archaeologist has unearthed fresh evidence to prove the existence of mass graves at the Nazi death camp Treblinka.
Some 800,000 Jews were killed at the site, in north east Poland, during the Second World War but a lack of physical evidence at the site has been exploited by Holocaust deniers.
Forensic archaeologist Caroline Sturdy Colls has now undertaken the first co-ordinated scientific attempt to locate the graves, according to an interview in the Radio Times.
As Jewish religious law forbids disturbing burial sites, she and her team from the University of Birmingham have used "ground-penetrating radar".
Her work at the site, where the Nazis tried to destroy all traces of industrial-scale killing, is being followed in forthcoming Radio 4 documentary The Hidden Graves Of The Holocaust.
The programme's presenter, Jonathan Charles, a former BBC foreign correspondent, wrote in the Radio Times that the ground-penetrating radar had also discovered the foundations of buildings and that two are likely to have been gas chambers.
Sturdy Colls said: "All the history books state that Treblinka was destroyed by the Nazis but the survey has demonstrated that simply isn't the case."
She added: "I've identified a number of buried pits using geophysical techniques. These are considerable in size, and very deep, one in particular is 26 by 17 metres."
The programme's presenter wrote in the Radio Times that the pits contain the burnt remains of thousands of bodies.
The forensic archaeologist, who has now presented her findings to the authorities responsible for the memorial at Treblinka, said: "I really hope this is the first stage in a long-term programme to seek out those hidden graves of the Holocaust."
Survivor Kalman Taigman remembers his arrival at the camp's railway station, packed into a cattle wagon.
"I was with my mother. We were about 100 people in a wagon. They opened the doors, firing guns and hitting us, and sent us into a yard. I ran with my mother and tried to calm her.
"They told me to leave my mother but I didn't do it quickly and I was hit on the head. When I got up, she was gone. She went with all the rest of the women to the gas chamber."
The Hidden Graves of the Holocaust is being broadcast on Monday January 23 on 8pm on BBC Radio 4.