DENVER -- When the Democratic National Convention rolled into Denver last August, the local Host Committee had proudly raised more than $55 million to cover costs.

Nearly a year later, Denver councilman Charlie Brown started to hear rumors of unpaid bills.

He did his own fact checking and went public with a mention in his popular newsletter, The Email Express.

"Rumors all over town are that the DNC still owes money to companies, (one confirmed) and local Denver vendors," Brown wrote.

"It was a great convention, but pay your bills,” Brown told 7NEWS Tuesday.

Brown explained he wasn’t singling out Democrats, but was disappointed to learn of outstanding expenses -- something he said has happened in other cities in the past.

“Both parties are notorious for not paying their bills after a convention. They leave town and then come back a month later and negotiate," he said.

Since publishing his newsletter nearly two weeks ago, Brown has remained mum about which company is owed money.

"It's a large amount of money we're talking here," he said.

Multiple sources later confirmed to 7NEWS that Xcel Energy, which donated more than a million dollars to the Democratic National Convention, is the company in question.

The dollar amount apparently owed to Xcel is in the neighborhood of $200,000 for power supplied to air conditioned tents during the DNC, sources told 7NEWS, speaking on the condition of anonymity.

“This happens to be one expense the Host Committee hadn't received yet,” said Mike Dino, CEO of the Denver Convention Host Committee said Tuesday.

“I learned of some of the details just today," Dino added.

He explained as of Tuesday, the Host Committee had not seen an invoice from Xcel.

"Today I did learn that Xcel has some expenses they'd like me to review, and I'm certainly glad to do that," Dino said.

Questions remained Tuesday why the Host Committee would just be learning of the apparent expenses. An Xcel spokesperson declined to comment on the issue citing customer privacy.

Dino would not confirm the dollar amount being discussed or what the power was used for during the Convention, but added his meeting with Xcel will take place this week.

"How can you not resolve something in a very friendly way with one of your best donors?" Dino asked. "We really appreciated how they stepped up to the plate early on for the Host Committee. I look forward to trying to meet their expectations and work with them on this," he continued.

Dino also explained it’s not unusual for expenses to be paid months later, and typically contractual arrangements like this would be negotiated through the Democratic National Convention Committee.

The DNCC would then approve expenses to be paid by the Host Committee. Dino said no such expense approval was received by the Host Committee.

A spokesman for the Democratic National Committee said he had no knowledge of outstanding expenses owed to Xcel.

Brad Woodhouse, Communications Director for the DNC, forwarded 7NEWS a statement from DNC legal staff. The statement referenced Master Contract 7.8. “All power up to a certain level was to be provided free by Pepsi Center, and above that level the Host Committee was responsible. In no event was DNCC ever obligated to pay for any power,” the statement said.

Dino called it a “manageable situation,” and continued to applaud Xcel, “They were a wonderful partner with the Host Committee helping to sponsor and underwrite the Convention,” he said.

He reminded the Host Committee planned to stay up and running for at least a year following the DNC.

Dino said insurance claims are also being worked out with companies like General Motors and Motorola.

Federal Election Commission documents show the Host Committee had $2.8 million worth of cash on hand, according to a quarterly statement filed in April.

A spokeswoman at Denver Mayor John Hickenlooper’s office said the mayor was aware of the claim and, “expects both sides will work everything out.”

Hickenlooper was not available for comment Tuesday.