Russian ships able to perform underwater operations were present near to where explosions later took place on the Nord Stream pipelines, according to an investigative documentary.
The vessels were reportedly located using intercepted Russian navy communications.
Underwater explosions last September knocked the two Nord Stream pipelines - built to carry gas from Russia to Europe - out of action.
The cause of the blasts is unclear.
In the immediate aftermath, some in the West pointed the finger at Russia, while Moscow blamed Western countries, including the UK.
More recently, there were reports that intelligence pointed towards pro-Ukrainian operatives, although not the Ukrainian government itself.
Sabotage
Formal investigations are still taking place in countries close to the blast site. So far, these nations have only said they believe the explosions were the result of sabotage rather than any kind of accident.
But the BBC says today the latest programme in the TV documentary series Putin's Shadow War and accompanying English language podcast Cold Front provides one possible lead pointing towards Russia's involvement.
The series by Denmark's DR, Norway's NRK, Sweden's SVT, and Finland's Yle broadcasters revealed last month that Russian vessels appeared to be mapping out wind farms in the North Sea, including off the UK coast.
Now, the latest episode focuses on what they say are suspicious ship movements in the run-up to the Nord Stream blasts.