WASHINGTON (AP) — The top GOP aide to a House committee investigating Solyndra Inc. once worked for a lobbying firm that helped the now-bankrupt solar company apply for a half-billion-dollar federal loan.

Gary Andres, staff director of the House Energy and Commerce Committee, was a vice chairman at Dutko Worldwide until last December, when he was appointed to his current post by Rep. Fred Upton, R-Mich., chairman of the energy panel. The committee is investigating Solyndra, which received a $528 million Energy Department loan in 2009. The company later went bankrupt and laid off its 1,100 workers.

The Kalamazoo Gazette reported Monday that Solyndra paid Dutko $30,000 in 2008 to handle its application for the federal loan.

Alexa Marrero, a spokeswoman for the committee, said Andres never worked on behalf of Solyndra and was not aware until recently that Dutko had represented Solyndra in 2008.

Marrero said the revelation that Solyndra hired Dutko, now known as Dutko Grayling, does not change the facts of the case.

"Despite serious warning signs from within the (Obama) administration that a federal loan to Solyndra would be a losing proposition, the Department of Energy gave a green light to a half-billion dollar loan to this company, followed by a restructuring that put taxpayers at the back of the line," she said. "Now the committee is asking what went wrong, and what can be done to ensure taxpayers aren't left on the losing end of this kind of bad bet ever again."

John Waltz, a Democrat running for Upton's seat in 2012, said Monday that Upton should have disclosed Dutko's involvement with Solyndra once he became aware of it. Andres should recuse himself from the Solyndra investigation, Waltz said.