The commission on Monday refused to dismiss the complaints after Gessler's lawyers contended the commission could be improperly acting as a criminal court.
Gessler is accused of spending about $1,500 from his office's discretionary fund to attend a conference of the Republican National Lawyers Association and the Republican National Convention in Florida last November.
According to the Denver Post, Gessler says he spent the money after death threats were made against his family, prompting his early return to Colorado.
An aide also says the office fund is similar to the per diem given state lawmakers where no receipts are necessary.
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