Latvians refuse to lift lid on KGB past
In Latvia this place is known as the House on the Corner - and for much of the 20th Century, as home to the KGB, it was the most feared building in the country.
Now, as Latvia marks 25 years since it declared independence from the Soviet Union, pressure is growing to publish the names of KGB agents who spied on their fellow citizens.
A stooped elderly man slowly opens the heavy metal door which half a century ago imprisoned him.
"It was deadly silent," he remembers with a sad smile. "And if you were brought out into the corridor and another prisoner came, you had to turn round to the wall, with your face to the floor, so that you didn't know who else was here."
In a beret, and with a distinguished white beard, Knuts Skujenieks, 78, is exactly how you would imagine a dissident poet from the former Soviet Union.
In 1962 he spent six months here, before being sent to a Soviet labour camp near the Ural mountains in Russia for more than six years.
His crime was writing poetry.
He believes his imprisonment was a warning to other Latvian writers not to agitate for independence from Moscow.
From the outside, the House on the Corner is an ornate Art Deco building, originally built as a chic apartment block for Riga's wealthy bourgeois elite.
After the Soviet occupation of Latvia during World War Two, it became the KGB's headquarters.
In the 1940s, prisoners were tortured and even killed here.
On one courtyard wall you can still see the hooks where inmates were hung up by chains, their feet dangling metres from the ground.
On the street, near the entrance, there used to be a small letterbox where Latvians could post requests for information about people who had been detained here; or, more chilling still, slip in notes informing the secret services of the suspected anti-Soviet activities of their neighbours, work colleagues or even friends.
It is this unsettling aspect of Latvian history which is today more explosive than ever.
Between the end of World War Two and the collapse of the Soviet Union in 1991 around 30,000 KGB agents and informers worked in Latvia - many of them Latvian.
Details of the victims can be found in hundreds of thousands of KGB files held in a cavernous former radio factory on the outskirts of town.
Here we find the files which list Mr Skujenieks' "crimes" - 16 thick handwritten volumes, stuffed with photographs and battered 50-year-old school textbooks containing Latvian poems written in faded pencil.
But what these files do not tell you is who did the spying.
The names of the KGB agents are in code. Their real identities are listed on 4,300 cards, stored in sacks and guarded by Latvia's authorities.
Every time the Latvian parliament is about to open these files, the move is blocked by certain senior politicians who want to hide their own past collaboration with the KGB, says historian Karlis Kangeris.
"Former KGB agents must admit to their past. Society can't forgive if we don't know what we're supposed to be forgiving."
But in the seaside resort of Jurmala, I meet the man whom some would hold responsible for some of the repression: the last boss of the KGB in Latvia, Edmunds Johansons.
A genial, chatty man, he is convalescing in a former Soviet sanatorium - a funky building from the 1960s hidden away deep in a forest and reminiscent of a baddy's lair in a James Bond film.
Mr Johansons will not me give any names, but he confirms that some leading figures in Latvian politics and society used to work for the KGB.
Opening up the files, he believes, would tear Latvian society apart.
"We'll just antagonise people. We should aim for consensus and harmony in society. We have to build a future for an independent Latvia. And not do the opposite, and look backwards. It's a very dangerous question."
Back in the prison, I am surprised when Mr Skujenieks tells me that he agrees.
Key data was taken back to Moscow when the Russians left, he explains, so the documents left behind in Riga are incomplete and misleading. And much of it cannot be trusted anyway, Mr Skujenieks says, citing dates and facts about himself in his files which he knows are lies.
"If Moscow would give us all the files it would make sense to open them up. But given the present political situation, it's 100% clear, that's not going to happen."
Mr Skujenieks suspects that the Kremlin is hanging on to the files in order to threaten Latvians and potentially destabilise society.
Two-and-a-half decades after declaring independence, Latvia is still under threat - not from the KGB, but from the files they left behind.