- Burning Brigade legend has persisted for 72 years.
- Scientists employ non-invasive methods to examine Holocaust burial site.
- Computation reconstructs underground images and confirms Ponary forest escape.
They emerged from their hand-dug tunnel on the darkest night of April 1944.
After months of digging with spoons found among the dead, this was their moment. They crawled through the two-foot-square tunnel, exited into the Ponary forest, and fled into the shadows.
Alerted by the noise, German guards quickly rounded on the escapees, and with dogs and guns killed all but the luckiest dozen.
Is this harrowing escape tale just a legend?
Trauma can mangle the memory, so scholars of the Holocaust seek verification. The tale told by the survivors of the ‘Burning Brigade’ – so-called because they were imported to burn the evidence of Nazi war crimes – is one that almost defies belief.
Almost.
Forensic archaeologists
Corroboration would come 72 years later, when a sub-surface mapping group found a way to peer underground without disturbing the burial pits in a northeastern Lithuanian forest.
The team, led by Richard Freund, a professor of Judaic studies at the University of Hartford, and Jon Seligman, an archaeologist with the Israel Antiquities Authority, was in nearby Vilnius, where they had successfully located the subterranean remains of the Great Synagogue of Vilnius.
Encouraged by these results, the administrators of the Lithuanian Vilna Gaon Jewish State Museum enlisted Freund’s team to help verify the location of the legendary Ponary escape tunnels that Lithuanaian archaeologists had found the entrance to in 2004. 
Freund is a historian and a trained field archaeologist, and his team has used ground penetrating radar (GPR) and electrical resistivity tomography (ERT) to non-invasively examine sub-surface materials over the last 20 years.
“Traditional archaeology is a destructive and very invasive method to achieve information on any site,” says Freund. “The Ponary site is filled with bodies and that makes it difficult for traditional archaeology to ever locate the tunnel without a potential desecration of the burials there.”
Tools of the trade
GPR gleans its answers from pulses of radio waves sent underground. Reflected back to a receiver, GPR waves reveal the obstructions encountered and paint a picture of the sub-surface. For Freund’s team, the GPR work was conducted by Harry Jol, professor in the department of Geography and Anthropology at the University of Wisconsin-Eau Claire. GPR data was prepared by Dean Goodman of GPR –Slice.
Normally used in the oil and gas industry, ERT allows a snapshot of the electrical properties of subsurface materials. The degree to which structures beneath the surface resist or conduct electricity reveal a lot about the underground composition.
For the Ponary project, ERT studies were conducted by geophysicists Paul Bauman and Alastair McClymont of WorleyParsons, Inc. in Calgary, Canada.
“We provide a MRI for the ground,” says Freund. “In the real world, we would never let a surgeon do major surgery until they had done X-Rays, an MRI, and consulted with a radiologist. Why not do the same for archaeological excavations?”
When scientists pass a radar wave or electrical current through the ground, they’ve only just begun. The heavy lifting remains for computers to complete. GRP and ERT generate the data, but the images of the substructure are reconstructed computationally via algorithm. An inverse and ill-posed problem, imaging the subsurface uses the results sent back from the tools to calculate the causes.
Freund says the team opts for both methods because of the advantages each brings to the research. GPR allows a look at large areas which are mapped out with GPS coordinates. ERT identifies very specific elements underground such as wood, metal, and bone, and allows for a much deeper view underground – up to 120 feet below the surface. All subsequent digital mapping was done by Philip Reeder, dean of the Bayer School of Science at Duquesne University.
Combining these two non-invasive techniques, Freund’s team found and verified the Ponary escape tunnel on June 8.
The brave and the horrible
The Burning Brigade’s tale is true. Conscripted to burn the bodies of 100,000 Nazi victims, these 80 Jewish inmates from the nearby Stutthof concentration camp knew they would join the other victims when their task was finished. By day they burned the bodies of the dead; at night they dug for their lives. After four months of this horrific pattern, they made their escape.
As the men and women surfaced from the tunnel and ran into the dark woods, their guards heard the noise. Of the 80 that exited the handmade portal, only 12 survived the hail of bullets.
Freund’s efforts now confirm one of the acts of resistance from the Holocaust. Computational assistance has made it possible to corroborate the testimony of the past, without disturbing the remains of the victims.
From one mystery to the next, Freund and his forensic geoscience team are now moving onto Israel. ERT and GPR have revealed the ancient floor of perhaps the most venerated church for early Christianity lies underneath the Greek Orthodox Church of the Annunciation in Nazareth.
“Geoscience is the new frontier for ancient and Holocaust archaeological studies. This is a technology whose time has come.”
