A three-year guessing game has been taking place on Wall Street to identify the Goldman Sachs employee behind a Twitter account that purports to reveal the uncensored comments overheard in the firm’s elevators.

The Twitter account, @GSElevator, reports overheard remarks like, “The NSA is the only branch of the government that actually listens to people,” and “Groupon...Food stamps for the middle class.”

The Twitter account, which has an audience of more than 600,000 followers, has been the subject of an internal inquiry at Goldman to find the rogue employee.

The tweets, often laced with insider references to deals in the news, appeal to both Wall Street bankers and outsiders who mock the industry. Late last month, the writer sold a book about Wall Street culture based on the tweets for a six-figure sum.

There is a good reason Goldman Sachs has been unable to uncover its Twitter-happy employee: he doesn't work at the firm. And he never did. The author is a 34-year-old former bond executive who lives in Texas. His name is John Lefevre.

After his identity was uncovered, Mr Lefevre confirmed his alter ego. "Frankly, I'm surprised it has taken this long," he said by phone. "I knew this day would come." Mr Lefevre, who worked for Citigroup for seven years, said the Twitter account started as "a joke to entertain myself."

He quickly interrupted the inevitable line of questioning about how he had never worked at Goldman and appeared to be an impostor. “To pre-empt what you’re about to say, legally speaking,” he said, “I was never explicitly an employee of the firm.”

Mr Lefevre was offered a job as head of debt syndicate in Asia at Goldman’s Hong Kong office in August 2010, but the offer was later revoked, according to people at the firm who spoke on the condition of anonymity because they were not authorised to discuss the matter.

By Lefevre’s own account of his experience with Goldman: “My contract was never rescinded. We cordially agreed to part ways to avoid a public mess. I don’t know how much I can talk about it. It wasn’t acrimonious.”

A Goldman spokesman, after being told that @GSElevator had been unmasked, said in a statement, "We are pleased to report that the official ban on talking in elevators will be lifted effective immediately." The New York Times

Some tweets from the @GSElevator Twitter account:

The NSA is the only branch of the government that actually listens to people.

1,000 credit card numbers stolen from Neiman Marcus are worth more than the 40 million stolen from Target.

The iPhone 5S is a great way for the NSA to build a fingerprint database.

In life, as in sports, the boos always come from the cheap seats.

Too many people still answer the phone like they don’t know who’s calling.

Being single at 40 is perfect. Divorcées chase me. Sweet spot for 30-somethings. Rich enough to get girls in their 20s.

Sure, I’ll have $6 bottle of Evian with a glass full of ice made from tap water.

Real estate brokers should use Groupon to see who’s about to go out of business.

If there really was a glass ceiling, we’d let all the women work above us.