Telopea Park is one of Canberra's oldest green spaces — it's a quiet narrow strip of parkland just a short walk away from the Russian embassy.

But at the height of the Cold War, when that embassy flew the hammer and sickle, Telopea Park was rumoured to be rife with espionage and intrigue.

A quick search online will tell you that it's a "well-known" dead drop zone — a previously agreed upon hiding place to swap secret documents without contacts ever meeting.

But try and find a source for that, and you'll quickly be met with whispers. It seems the Cold War era is determined to hang onto its secrets.

Curious Canberra has been tasked with solving the Telopea Park rumour by Rebecca Scouller, a public servant who "probably shouldn't say" which department she works for.

She asked: Was Telopea Park a spy drop off point?

"I walk through Telopea Park on a pretty regular basis, and I think the history and the stories that go with the park make it a little bit more intriguing," Ms Scouller said.

She thinks "it possibly is true" but wonders exactly how they did it.

ASIO looked for clues

Chasing answers about Cold War spying isn't a walk in the park.

Authors and archivists wouldn't talk, others did — but not on the record — and former spies proved difficult to trace (for obvious reasons).

But the Australian Security Intelligence Organisation (ASIO) certainly believed Telopea Park was being used by Soviet agents.

Loading...

Surveillance footage from the time shows Australian officers scouting out the park for possible hiding spots.

They were hoping to expose sites that the KGB, the Soviet Union's chief security agency, were using to share information without meeting contacts in person.

In one incident, a suspected KGB officer was followed into Telopea Park "to see whether [he] was looking for dead letter box signs", according to the 1963-1975 edition of ASIO's official histories.

All that's recorded of the pursuit is that the surveillance "did not provide any leads", and that officers didn't maintain a safe distance.

"You won't find any sources for it, I don't think," local historian Dr Peter Dowling said.

Dr Dowling is also elusive about his work: he prefers to say that he formerly worked in "defence communications".

"It's all pretty much rumour and innuendo. But I think it's fairly strong rumour and innuendo," he said.

Dr Dowling may be right: a source familiar with the ASIO files from the Cold War era said the use of Telopea Park was never confirmed in any documents they have seen.

"It's murky business ... the real goings on will probably never be fully substantiated. That's all I can really say about Telopea Park," Dr Dowling said.

A former spy weighs in

Former ASIO spy Molly Sasson worked with the MI5 before she accepted a job in Canberra. ( Supplied )

But a former spy for ASIO, who broke her silence in 2015, has one anecdote that could solve this mystery.

Molly Sasson was the first female intelligence officer on the Soviet espionage desk in Canberra.

Two years ago she spoke to the ABC about her suspicion that ASIO had been infiltrated by a mole.

Ms Sasson had been following suspected Russian agent Vladimir Dobrogorsky for some time, and believed he was running an agent in Australia.

The Soviet desk believed that Mr Dobrogorsky was about to exchange documents in a rendezvous with an unknown Australian at Telopea Park.

"It was all set for 6:30pm," Sasson told The Australian.

"We had everyone in place, but it never happened because he didn't turn up.

"We later found out that on that morning he had left the [Soviet] embassy for Sydney and caught a plane to Moscow. He never came back. I am convinced that someone within ASIO tipped him off."

Despite several attempts, Curious Canberra was unable to reach the former spy for further comment. Seems she's flying under the radar again.

For now, her account is the closest we can get to the truth — and if you can't trust a spy, who can you trust?

One drop off point we can verify

Whether Telopea Park was used or not, there's no doubt spies ran amok in Canberra, following targets to tailors, to the Narrabundah shops, and through the Kingston Hotel.

At an underpass of a railway bridge in Hume, on the ACT border, Australia's most famous Cold War case began: the defection of KGB agent Vladimir Petrov.

"That [the railway bridge] was used as the drop off point for information between Petrov, who was at the Soviet embassy at the time, and ASIO agents to exchange information," said Dr Dowling.

Perhaps most absurd is the fact that a funeral parlour opposite the Soviet embassy in Griffith leased a room on its floor to ASIO.

"The window was always open up there, so it was common knowledge ... that ASIO were watching the gates," said Dr Dowling.

Mystery still surrounds the upstairs room of Tobin Brothers Funeral. ( ABC News: Jake Evans )

"That's part of the big game."

If Telopea Park ever was used by spies, today it's more likely to be a drop off point for kids heading to the playground than for secret documents.

So, are mysterious figures peering from funeral parlour windows and letters exchanged under cover of darkness now merely shadows of the past?

Perhaps.

But the upstairs room of the funeral home is locked to this day.

And Tobin Brothers Funeral doesn't have the key.