In the sprawling Dablice cemetery in Prague's northern suburbs, two archaeologists kneel in the dirt in a square hole around a meter deep.

Working in silence, they brush away soil from fragments of wood as a gentle drizzle patters on the white plastic tent erected over their heads.  

"This place is seen as sacred for political prisoners, especially the political prisoners of the 1950s, when many of them were sentenced to death," said Jiri Linek, head of the Association of Former Political Prisoners 1948–1989.

Linek has made it his life's work to bring clarity to this mournful chapter in Czech history.

Now, for the first time since 1989, the state is overseeing the exhumation of graves believed to contain the remains of political prisoners.

Execution of decorated war heroes

"According to the available records, this grave — Mass Grave No. 14 — should contain the remains of three officers involved in the planned anti-communist uprising of 1949 known as 'Prague–Zatec,'" Linek told DW.

The three officers — Karel Sabela, Vilem Sok-Sieger and Miloslav Jebavy — were decorated war heroes, men who had fought the Nazis in France, North Africa and at home in what was then Czechoslovakia.

When the Communists took power in February 1948, the three men began planning a military coup aimed at overthrowing the nascent Stalinist regime.

According to their plan, Sabela's tank unit from the military garrison in Zatec was to move to Prague and assist in seizing key strategic locations such as ministries, the headquarters of Czechoslovak Radio and the telephone exchange.

Secret police, however, infiltrated the group and the operation was foiled before it began. Several dozen participants were put on trial. Five were hanged immediately; others received life sentences.

The right to a dignified burial

"Every person has the right to a dignified burial. And for victims of totalitarian regimes — who were not allowed that right — it is absolutely justified," said Petr Blazek, a historian specializing in the communist period.

"It's also the duty of the state to honor people who resisted totalitarianism and to show, through their stories, what that regime was really like," he went on.

Historians still debate how real the coup plan was and how much was fabricated or manipulated by the regime to purge dissent.

Some sources suggest the secret police (the StB) may have provoked or exaggerated the plot to justify the arrests.

Reburial with their loved ones

"These people were victims," Blazek told DW. "It is absurd that some of them are buried here together with people who were murderers or convicted criminals."

There is, of course, a strong human element.

Several descendants of the army officers were present at the first day of the exhumations. They provided DNA samples to be compared with the corpses of the three men, once the correct bodies have been identified and removed from the mass grave.

If the match is complete, they will finally be reburied alongside their loved ones.

Social graves used for executed dissidents

"We know that there are four layers of coffins, and 10 coffins in each layer. So, there are 40 coffins in each mass grave," said Martin Cechura, an archaeologist from the Museum of Prague.

"But we also know that each coffin may contain several individuals. Mass Grave No. 14 should contain the remains of 281 people — not only political prisoners; far from it," he went on.

"You see, these were social graves, where people without relatives were buried, stillborn babies, people whose bodies were dissected at the anatomy institute, and even amputated body parts," Cechura added.

Untangling this puzzle, sorting through this collection of corpses to extract the three executed officers is a task that requires great dignity and care.

Ultimately, it will go toward righting a historical wrong.

"Social graves were not invented by the communist regime. They have existed in Christian cemeteries since the Middle Ages. They were intended for people who had no one to bury them, no one to arrange a funeral," Cechura said.

"Of course, the regime used — or rather misused — these social graves to bury the victims of its repression. They treated them as if they had no relatives, even though they did. It was another level of punishment for the families, who were never told where they were buried," he added.

Solving an enduring mystery

There could be several hundred communist-era political prisoners buried here. Some are already honored with named plaques, the work of Jiri Linek and his organization, but many are not.

In time, he hopes, the ultimate mystery will be solved, one that has eluded Czech historians for decades.

In May 1942, a pair of British-trained paratroopers — Jozef Gabcik and Jan Kubis — assassinated Reinhard Heydrich, the acting Nazi Reichsprotektor of Bohemia and Moravia, one of the key architects of the "Final Solution."

They were part of a group of seven men who three weeks later were surrounded in the crypt of a Prague church after being betrayed. Following a gun battle with German SS and Wehrmacht troops, they took their own lives.

That much is known. But the question remains: Where are the bodies?

"We have confirmed that the Germans transported their remains to the Prague Institute of Anatomy. But what happened after that, we just don't know," historian Petr Blazek told DW.

"We know that Kubis and Gabcik's bodies were decapitated, but as for what happened next … the usual practice of the Anatomical Institute was to send remains here to Dablice, to these social graves," he went on.

There is already a special plaque to the seven paratroopers a short distance from the communist-era plots, based on information provided to a researcher by one of the former employees of the institute.

But whether their bodies truly lie here is unknown. And there is only one way to establish that theory beyond doubt.

Edited by: Aingeal Flanagan