The Federal Election Commission (FEC) has sent a second letter to Newt Gingrich's campaign asking them to explain why almost $1 million dollars was paid to a small group of people including the presidential candidate.

The Washington Times reported on Wednesday that Gingrich, members of his staff and several consultants received "questionable reimbursements."

In January alone, a small group of people within the campaign were paid $220,000 on top of their salaries. That figure included the $88,000 Gingrich paid himself for unspecified "travel" expenses, according to reports filed with the FEC Monday.

The latest FEC filing comes as a shock because Gingrich spokesman R.C. Hammond had told the Times that the campaign would no longer need to reimburse the candidate after finally obtaining a credit card late last year.

The government watchdog Citizens for Responsibility and Ethics in Washington (CREW) filed a complaint (PDF) with the FEC in December, charging that he had illegally used campaign funds for personal use.

"We based our complaint on ABC News and Washington Post stories about these joint events and they seem to be for a dual purpose, for promoting his candidacy and promoting books," CREW executive director Melanie Sloan told ABC News.

"The FEC needs to investigate this," she added. "What they should do is investigate and get some answers from Gingrich and they should fine him if he's found to be in violation."

In one instance, the former House Speaker paid himself $42,000 for the use of his personal mailing list. The campaign also racked up $1.2 million in debt by chartering $30,000 jet flights and booking upscale hotels.

The Washington Post estimated that the campaign had spent $3 for every $2 it raised.