While Energy Department officials steadfastly vouched for Solyndra -- even after an earlier round of layoffs raised eyebrows -- other federal agencies and industry analysts for months questioned the viability of the company. Peter Lynch, a longtime solar industry analyst, told ABC News the company's fate should have been obvious from the start.

"Here's the bottom line," Lynch said. "It costs them $6 to make a unit. They're selling it for $3. In order to be competitive today, they have to sell it for between $1.5 and $2. That is not a viable business plan."

Other flags have been raised about how the Energy Department pushed the deal forward. The Center for Public Integrity's iWatch News and ABC disclosed that Energy Department officials announced the support for Solyndra even before final marketing and legal reviews were in. To government auditors, that move raised questions about just how fully the department vetted the deal -- and assessed its risk to taxpayers -- before signing off.