WASHINGTON (Reuters) - A former accountant at the U.S. Securities and Exchange Commission on Tuesday settled parallel criminal and civil charges, after he was caught illegally trading options and lying about it while employed at the agency.

David R. Humphrey, 60, who worked in the SEC’s Division of Corporation Finance for 16 years, pleaded guilty to filing false ethics forms in order to conceal his trading, the Justice Department said.

The SEC also filed civil securities fraud charges against Humphrey, saying he “largely conducted this improper trading strategy using his SEC computer during business hours,” filed false ethics forms disclosing his holdings and traded other prohibited securities, including put options on Citigroup shares.

This trading, the SEC added, was conducted for his own accounts, as well as for his mother and a friend. When he was confronted by agents in the SEC’s inspector general’s office in 2014, the SEC said, he continued to lie about his trading.

In a settlement, Humphrey will pay more than $108,000 in penalties, ill-gotten profits and pre-judgment interest and will be permanently suspended from practicing as an accountant on SEC matters, the regulator said.

Kenneth Lench, an attorney for Humphrey, said his client

“accepts responsibility and is looking forward to putting this matter behind him.”

The SEC’s charges against Humphrey represent a rare instance of the agency taking enforcement action against one of its own employees.

While other former SEC staffers have faced criminal prosecutions for ethics violations related to trading, the SEC did not take parallel civil actions against them.

The SEC’s choice to invoke civil securities fraud charges against Humphrey for ethics violations is also unusual. Typically, such charges are levied against individuals and companies that defraud investors.

The use of securities fraud charges is “unorthodox,” said Matthew Solomon, a partner at Cleary Gottlieb Steen & Hamilton who previously served as the SEC’s top litigator.

“Fundamentally, this is a case about lying on government forms, which is classically criminal in nature.”

Reuters first reported about the pending charges against Humphrey last week.

The SEC has strict securities trading rules for its employees, as many of them have access to non-public and potentially market-moving information.

SEC employees are banned from holding stock in companies directly regulated by the SEC, such as banks, and they are also required to get clearance prior to trading. Trading in options is also banned.

Humphrey is not accused of using material non-public information for his trades, and in fact the SEC said he often suffered “significant losses.”