A retired chef and grandfather, Bob Nelson, has a warning to others about an increasingly common scam — investing in cryptocurrency.

“It’s an awful, terrible feeling to know your whole life’s savings in one second is just gone,” Nelson said.

Nelson sits in his dining room, reflecting on his empty bank account, wondering how he will continue supporting himself, his daughter, and four grandchildren after a romance scam wiped out his money.

“I’m depressed and embarrassed I fell for this,” Nelson said.

In August, recent widower Nelson got a chat request online from a young woman named Cindy Smith. He was lonely and worried about how long his savings would last to support his family.

After a few pleasurable weeks of chatting with Cindy, she had some advice.

“She started mentioning bitcoin and how much money she was making with bitcoin futures,” Nelson said.

But before Nelson invested, he hired a private investigator to check Cindy out.

It turns out her name wasn’t Cindy — and the driver’s license she’d sent him a copy of was fake.

But she did appear to be a real person with an accurate profile under another name, so Nelson, thinking she was protecting her privacy by using the Cindy Smith Facebook page, deposited money in what appeared to be an accurate cryptocurrency exchange.

“I sensed that I had enough information about her that I could track her down, or the police could track her down,” Nelson said.

Nelson even withdrew most of his money once to ensure he could. Reassured, he re-deposited it.

But Nelson underestimated how tricky this scam could be.

After a month of getting supposed 20% returns, the scammers locked his account when he tried to withdraw money a second time.

Nelson got a call from a Secret Service agent who said an international ring of thieves duped Nelson — that they’d copied the cryptocurrency exchange website and stolen his life’s savings.

“Many of these scams involved fake crypto exchanges or exorbitant fees to withdraw money,” Better Business investigator Marc Simmons said. Simmons said these are the third most common types of online scams.

Simmons says the bitcoin thefts often start just like Nelson’s did — as a romance scam — and never end well.

“So if somebody’s mentioning bitcoin futures, stay away, stay away,” Nelson said.

Nelson said after finally confronting the scammer, she and her cohorts repeatedly called and taunted him, even making threats against him and his family.

WPBF 25 News Investigative Reporter Terri Parker called the Secret Service agent investigating this case — he referred her to a spokesman who has not yet reached them.

Parker also called a “Cindy Smith” number that went straight to voicemail.

Investigators say don’t fall for someone online with investing advice — ask your banker, a financial adviser, or a trusted relative.