The series finale of hit television show Sherlock was leaked online following a cyber-attack by hackers, Russia's Channel One has confirmed.
A Russian-language version of the 90-minute episode appeared online on Saturday, a day before the program's planned Sunday night broadcast.
Channel One, who holds the rights to air Sherlock in Russia, said that they were working with the show's producer and distributor, BBC Worldwide, in a bid to find the source of the breach.
"Channel One has been in close contact with the BBC from the moment we became aware of the breach," the media outlet said in a statement. "We are conducting an investigation to identify the source of the information that was released online, but preliminary signs indicate that the leak was due to a cyber-attack. We will be sharing all information on the leak with our colleagues as soon as this investigation is completed," a spokesperson said.
Earlier today, BBC Worldwide told The Telegraph newspaper that it had “initiated a full investigation” into the incident.
"BBC Worldwide takes breaches of our stringent content security protocols very seriously and we have initiated a full investigation into how this leak has occurred,” a spokesperson told the newspaper.
Sherlock is one of the BBC's biggest most profitable franchises, with the 2015 Christmas special “The Abominable Bride,” being sold to 216 territories.