The Justice Department has launched a inquiry into the sudden collapse of Silicon Valley Bank, according to a person with direct knowledge of the investigation.

Federal prosecutors are starting to ramp up a probe into the doomed Silicon Valley Bank just days after a bank run led to its swift collapse. In response, the the Biden administration took extraordinary measures to shore up billions of dollars in deposits to contain contagion from spreading across the banking sector.

While the exact nature of the investigation remains unclear, a source familiar said a formal announcement from the Justice Department is expected in the coming days.

According to former federal prosecutors, one area that may intrigue Justice lawyers involves shares sold by top company executives before the bank imploded.

Silicon Valley Bank CEO Greg Becker sold $3.6 million of company stock two weeks before the bank reported massive losses in the run up to the bank's implosion, according to regulatory filings.

"A top company executive engaging in a significant financial transaction so close to a cataclysmic event makes sense as something that would be interesting to prosecutors," said Tamarra Matthews Johnson, a former Justice Department lawyer who is now in private practice.

The sale has triggered new scrutiny of Becker and prompted some politicians to call for him to give the money back.

Becker has not been accused of any wrongdoing in connection with the stock sale. Becker did not return NPR's request for comment.

The Wall Street Journal earlier reported news of the Justice Department investigation.

On Friday, the Federal Deposit Insurance Corporation seized the bank, which had some $175 billion in deposits. The vast bulk of the accounts were uninsured. Federal deposit insurance generally only guarantees up to $250,000.

Treasury officials intervened and waived the cap in order to fully backstop depositors with an insurance fund backed up bank fees.

Although officials said the plan to rescue the bank did not include taxpayer money, and did not help the bank's management or investors, experts have called the intervention a bailout.

Silicon Valley Bank, which was highly concentrated in the tech start up and venture capital world, had for some four decades been a centerpiece of the venture-backed startup economy.

The demise of the bank has sent shock waves across the tech sector; startups who were facing financial challenges before the bank's failure are now bracing for them to be exacerbated.

While the federal government's actions to support uninsured deposits provided a ray of hope for customers of the bank, uncertainty persists among companies in a days since regulators announced the rescue deal.

Before officials in Washington unveiled emergency steps to protect Silicon Valley Bank depositors, outspoken venture capitalists and leaders in the startup community pleaded with the government for a safety net for depositors, forecasting a doomsday scenario for the tech industry in the absence of federal action.

When it became clear that Silicon Valley Bank may be in trouble, prominent venture capital firms, like Peter Thiel's Founders Fund, advised companies to pull money out of the bank. Bloomberg reported that Founders Fund itself yanked millions out of the bank in the lead up to the bank's meltdown. The actions have raised questions about whether venture capital firms that encouraged depositors to flee fueled the bank run that precipitated the bank's insolvency.

"I see this almost as an autopsy. It's incredibly important to find out how and why this has happened," said former Justice Department lawyer Matthews Johnson.