WASHINGTON — A political committee supporting President Barack Obama is out with a new ad accusing Mitt Romney of making millions while shutting down an Indiana paper plant.

The ad, from Priorities USA Action, is the latest in a series attacking Romney’s record at the investment firm Bain Capital. The group says it’s spending $10 million to air a total of four ads in Colorado, Florida, Ohio, Pennsylvania and Virginia.

The new ad features an employee of the AMPAD plant in Marion, Ind., Mike Earnest, recalling being told to build a stage from which company officials later announced mass layoffs. He says, “It was like building my own coffin.”

Romney aides contend AMPAD was in a struggling business to begin with, and Bain overall created many more jobs than were lost.