WASHINGTON (Reuters) - Keith Gill, the office worker who shot to notoriety after his online personas and bullish bets on GameStop ( GME ) sparked a retail trading frenzy, appears to be re-emerging from obscurity.

Known as "Roaring Kitty" on YouTube and "DeepF***ingValue" on Reddit's popular WallStreetBets, Gill was a key figure in the so-called "Reddit rally" in which shares of GameStop ( GME ) surged 1600% at one point in Jan. 2021, crushing hedge funds that had bet against the videogame retailer.

But after drawing congressional and regulatory scrutiny for his role in the extraordinary saga, Gill quickly disappeared, albeit much richer thanks to his GameStop ( GME ) investment which at one point reached $48 million in value.

For three years, Gill's accounts on YouTube, X, and Reddit lay dormant. He did no media interviews and when film-makers came knocking he declined to participate in their projects.

Then out of the blue Gill appeared in recent weeks to resurface online, sending GameStop's ( GME ) shares soaring once again.

On Monday, they rose 21% after Gill's Reddit account posted a screenshot showing a $116 million bet on the stock. On Thursday, they surged almost 50% after Gill's YouTube account scheduled a livestream for 12 p.m. ET (1600 GMT) on Friday.

The post, featuring Gill's trademark cat, sparked a deluge of excited messages from his followers, many of whom have likened the social media phenomenon to a David who took on Wall Street's Goliaths and won.

"I will watch this screen without blinking all night," a user with the handle Clay DeNicola posted on Gill's YouTube channel on Thursday.

Gill has not responded to multiple attempts by Reuters to contact him.

Born in 1986 to a truck driver and nurse, Gill grew up in Brockton, Massachusetts. "I grew up playing videogames and shopping at GameStop ( GME )," he told lawmakers during a 2021 hearing.

He graduated from Stonehill College in 2009 and between 2010 and 2014 worked at a start-up where he tried to build software to help investors analyze shares, according to his testimony.

"My salary never exceeded $40,000, but I did learn something about investing. I learned how to do the tedious work of digging through a company's financials and focusing on its real long-term value," he said.

"TOO LATE TO BUY?"

While unemployed in 2017 Gill, a husband and father, began analyzing stocks and investing his savings, an interest he "pursued passionately" even after taking on a marketing and financial education job at MassMutual in April 2019.

When in early June GameStop's shares fell on worse-than-expected earnings, Gill spied an opportunity. Believing the stock was trading below its fair value, he bought GME options and from there continued to add to his position, he said.

Gill began sharing his positions on WallStreetBets in September 2019, posting a screenshot indicating he had invested $53,000 in GameStop ( GME ).

With exuberant YouTube streams in which Gill frequently wore a bright red pirate bandana as he made the bull case for GameStop ( GME ), and Reddit posts touting his positions, Gill helped to attract a flood of retail cash into the beleaguered bricks-and-mortar retailer.

By late Jan. 2021, Gill was up over 4,000% on stock and options in the company, with his GameStop ( GME ) position plus cash worth nearly $48 million, according to his posts.

In an April 16, 2021 WallStreetBets post, which would be his last for three years, Gill shared screen shots showing he had exercised call options on GameStop ( GME ) to acquire 50,000 more shares in the retailer, sparking thousands of comments lauding the punchy move.

Now that Gill is back in the limelight, he is also back in the crosshairs. The Massachusetts securities regulator, which had opened and closed a probe into Gill, has said it is again reviewing his activities. The Securities and Exchange Commission is also reviewing his trades, the Wall Street Journal reported.

The agency has declined to comment.

Some have accused Gill of causing huge losses for investors who followed him into GameStop ( GME ), a claim he has long denied.

"I was abundantly clear that my channel was for educational purposes only, and that my aggressive style of investing was unlikely to be suitable for most folks," he told lawmakers, adding his investment thesis focused purely on GameStop's ( GME ) fundamentals.

Still, on Thursday many of his followers were contemplating buying more GameStop ( GME ) shares, with one handle George Black asking the group: "Is it too late to buy?"