PORTLAND — A Topsham woman pleaded guilty to a charge of theft by a Brunswick credit union employee today in U.S. District Court.

Marsha Richard, 42, was accused of stealing more than $500,000 in Atlantic Regional Federal Credit Union funds between November 2004 and October 2010.

Richard was accused of manipulating accounting entries for checks that credit union members had deposited but had been returned for insufficient funds. Richard allegedly credited her own account or those of family members or friends rather than to the appropriate internal account.

Richard faces up to 30 years in prison and a fine of up to $1 million.