A young American CEO who apparently committed suicide in Singapore was dealing in bitcoin, but was also struggling with other issues prior to her death, friends and colleagues said.

Autumn Radtke, chief executive of virtual currency exchange First Meta Pte Ltd, was found dead on February 26. Police said they were looking into her "unnatural” death, and "preliminary investigations showed no foul play is suspected.”

Neighbors said they thought Radtke jumped to her death from an apartment complex near her home.

Friends and colleagues said Radtke, 28, was wrestling with professional and personal pressures, not least running a startup that was struggling to gain traction.

"She had a phenomenal network of highly successful people around her, and here she is running this little exchange and it just isn't taking off in the way anybody had hoped,” said Steve Beauregard, CEO and founder of GoCoin, a startup which provided bitcoin-related services to First Meta.

He rented a room in Radtke's large Singapore home and was among the last people to see her alive.

Bitcoin is under scrutiny after Tokyo-based Mt Gox, once the world's dominant exchange for the virtual currency, filed for bankruptcy in Japan last week, blaming hackers for the loss of 850,000 bitcoins worth more than US$550 million.