Accepting, and then refusing to return, campaign cash from Charlie Rangel isn’t U.S. Rep. G.K. Butterfield’s only ethical hurdle as the fall campaign season gets under way.

The Democrat from North Carolina’s 1st Congressional District also faces an ethics probe for potentially misusing taxpayer funds on foreign travel, reports The Wall Street Journal.

Butterfield is one of a half-dozen House lawmakers in hot water over the travel:

The investigation follows a Wall Street Journal article in March that said lawmakers had used daily cash stipends, meant to cover certain costs of official government travel overseas, to cover expenses that appeared to be unauthorized by House rules. An independent ethics board has referred the matter to the House ethics committee.

Congressional rules say the daily travel funds, called a per diem, must be spent on meals, cabs and other travel expenses. But when lawmakers travel, many of their meals and expenses are picked up by other people, such as foreign government officials or U.S. ambassadors.

That can leave lawmakers with leftover money. Lawmakers routinely keep the extra funds or spend it on gifts, shopping or to cover their spouses’ travel expenses, according to dozens of current and former lawmakers.

In January, Carolina Journal reported on Butterfield’s pricy travel to Copenhagen for climate-change talks. The total bill was $4,406 for food and lodging at the five-star Copenhagen Marriot Hotel.