The politically connected solar firm that announced its impending bankruptcy last week was raided by federal agents this morning as part of a joint investigation between the FBI and the Energy Department Inspector General’s office.

The company, Solyndra Inc., had received significant favorable treatment from the Obama administration. One of the company’s primary investors, Oklahoma oil man George Kaiser, was also a major donor to the Obama campaign – a fact that raised concerns of political favoritism in the $535 million loan the company received from the federal government.

The San Francisco Chronicle reported on the raids Thursday morning:

FBI agents are serving search warrants this morning at Solyndra, the Fremont solar company that abruptly closed last week, an agency official said.

The search is part of a joint investigation involving the FBI and the Department of Energy’s Office of Inspector General, said FBI spokeswoman Julianne Sohn, who declined to elaborate.

Solyndra closed its doors on Aug. 31. It did so without warning and without WARN, a state and federal law requiring advance notice of a large layoff or shutdown. The company has said it was most likely exempt from notifying its 900 full-time and 200 contract workers ahead of time under a loophole in the law, officially known as the Worker Adjustment and Retraining Act.