Police investigating 'unnatural' death of Bitcoin exchange chief Autumn Radtke

The 28-year old computer expert was found dead at a Singapore apartment

Autumn Radtke poses next to Virgin founder Richard Branson (TWITTER)

Singapore police are investigating the "unnatural" death of a Bitcoin exchange chief executive.

Autumn Radtke, a US citizen based in Singapore, was found dead at an apartment block on 26 February.

Police said they were alerted by a phone call requesting assistance and "preliminary investigations showed no foul play is suspected".

The 28-year-old computing expert joined First Meta, a Singapore-based "pioneer in digital banking and virtual currency", as chief executive in January 2012.

She had previously worked for Apple as a freelancer and Virgin Charter.

First Meta said in a statement: "The First Meta team is shocked and saddened by the tragic loss of our friend and CEO Autumn Radtke.

"Our deepest condolences go out to her family, friends and loved ones. Autumn was an inspiration to all of us and she will be sorely missed."

Her final post on Facebook was a link to an article entitled "The Psychological Price of Entrepreneurship" detailing the stress and challenges of running a business.

She added: "Everything has a price".

Steve Beauregard, chief executive and founder of Singapore-based GoCoin, was among the last people to see Radtke alive.

"This wasn't a bitcoin-related death. She had other things going on in her life. Collectively, there were a lot of small factors. ... It appears she picked a permanent solution to a lot of short term problems," he told Reuters.

The news follows a tumultuous week for virtual currencies. Last Friday, Tokyo-based Mt Gox, filed for bankruptcy protection, while earlier this week Canadian Bitcoin bank Flexcoin collapsed.