RALEIGH, N.C. — North Carolina utilities regulators are disclosing internal materials collected from Duke Energy Corp. in an ongoing investigation into its takeover of Progress Energy Inc.

The North Carolina Utilities Commission on Tuesday posted more than 600 pages of emails and other information Charlotte-based Duke delivered to the regulator. Another 1,200 pages of documents that the company filed with the state are confidential and not open to public review.

The commission and Attorney General Roy Cooper demanded documents as they investigate Duke's surprise decision to change a key detail of its takeover even as regulators were considering approval – who would lead the combined company.

Progress Chief Executive Bill Johnson, who had been slated to become the top executive at the firm after the merger, was forced to resign by the Duke-controlled board within hours of the July 2 merger. The board then named Duke CEO Jim Rogers, who was supposed to be chairman of the utility, to replace Johnson.

The few nuggets in the public documents include a statement from Duke board member Dan DiMicco in November 2010, when the two companies were still negotiating a deal to become the nation's largest electric utility.

DiMicco said in an email that he thought it was a bad idea to give Johnson a two-year trial period as CEO.

"He's either the right guy or he's not. If he's not, then it is a deal-breaker for me," he wrote.

Rogers said in a May email that he feared the new company wouldn't value women. He said two female Duke executives decided to take other jobs after having "disheartening conversations" with their new bosses from Progress.

There is another email from a current Duke board member expressing confidence in Johnson to lead the new company, and there are plenty of documents related to the rush to get the Duke board together to vote on ousting Johnson.