The soldier accused of killing 16 Afghan civilians this month ran afoul of financial regulations more than a decade ago when he worked as a stockbroker. He was fined for defrauding a couple from Columbus, Ohio, and when the fine was not paid he was suspended from the brokerage industry, officials said on Monday.

Lawyers for the soldier, Staff Sgt. Robert Bales, 38, have said he was inspired to join the military after the attacks of Sept. 11, 2001, and friends and neighbors have said in interviews that he left behind a promising business career to serve his country. But records from the Financial Industry Regulatory Authority, or Finra, show that he and several colleagues were accused of fraud the previous year, in May 2000, in a case that led to more than $1.2 million in fines in 2003.

The case stems from Mr. Bales’s days as a broker at a securities firm in Ohio, where he sold stocks and bonds to retail investors. He and several colleagues were accused of selling unsuitable and overly risky investments. The case, regulatory records show, involved the stocks of Stearns & Lehman, a specialty food products company, as well as Orange County bonds and various mortgage investments, including products issued by Freddie Mac.

The brokers denied wrongdoing, sending the matter before a Finra arbitration panel, which in 2003 ruled against Mr. Bales and his co-defendants. The panel, saying Mr. Bales had “engaged in fraud, breach of fiduciary duty” and “unauthorized trading,” fined most of the brokers more than $1.2 million in punitive and compensatory damages.