* Parents hope for clues on why daughter, 15, died
* Verdict applies to other social media -court
* Sets important precedent in uncharted digital territory (Adds Facebook and activist group comments, background)
By Riham Alkousaa
BERLIN, July 12 (Reuters) - Heirs in Germany have the right to access the Facebook accounts of their deceased relatives, a court said in a landmark privacy ruling on Thursday, saying a social media account can be inherited in the same way as letters.
The Federal Court of Justice in Karlsruhe ruled that the mother of a 15-year-old girl who was hit by a train in Berlin in 2012 could gain access to her daughter's Facebook account, which social network locked for privacy reasons.
Facebook, whose 29 million active users in Germany equate to more than a third of the population, said that weighing the wishes of relatives against protecting user privacy is one of the toughest decisions the company faces.
"While we respectfully disagree with today’s decision ... the lengthy process shows how complex the issue under discussion is," a company spokesman said.
The deceased girl's parents wanted access to her account to try to find out whether her death had been by suicide or accident.
Facebook had turned the girl's profile into a 'memorial' page, where access to the user data is denied even though the content is still stored on Facebook's servers.
A lower court had ruled in favour of granting the parents full access to their daughter's account data. Facebook appealed against that decision.
The ruling sets an important precedent in Germany. The country, seeking to learn from its 20th century history of Nazi and Communist totalitarian rule, has privacy laws designed to protect individuals against intrusion.
"Today's verdict also affects other social media accounts, not just Facebook but Instagram and so on. So it's a verdict with very far-reaching consequences," a Federal Court spokeswoman said.
The decision comes less than two months after the European Union introduced a new privacy regime, the General Data Protection Regulation (GDPR), to strengthens people's rights to their data and how companies handle it.
Facebook, meanwhile, has come under fire over the leak of personal data on as many as 87 million users by a UK-based researcher to a consultancy that advised U.S. President Donald Trump's election campaign. The company was fined on Wednesday by Britain's data privacy watchdog.
Privacy campaigners welcomed the court ruling as a step towards regulating the "new land" of social networks and digital privacy.
"The ruling should be an impetus for German policymakers to regulate the digital estate," said Alex Fanta, a journalist at netzpolitik.org, a German news site that focuses on digital rights.
A recent survey by the German information technology association, Bitkom, showed that 49 percent of internet users said they did not care about what happens to their social media profiles after they die.
Ulf Buermeyer, head of the Society for Civil Rights in Berlin, said that the easy acces state agencies have to nearly all data on social networks' servers is a far greater concern than whether relatives can access it.
"While the parents of the deceased had to spend years litigating to read their daughter's messages, the National Security Agency and the Federal Intelligence Service would only need a few mouse clicks," Buermeyer said, referring to the U.S. and German intelligence agencies. (Reporting by Riham Alkousaa and Reuters TV Editing by Douglas Busvine and David Goodman)