Erika McCauley was arraigned Thursday and ordered held on $1 million bail.
Darryl McCauley, Cook's half brother and McCauley's husband, pleaded not guilty in March to larceny and forgery.
Authorities say state police recently found more than $700,000 hidden in the McCauleys' homes in Wilmington, Mass., and York Beach, Maine. State police found nearly $900,000 in December.
Prosecutors say Darryl McCauley stole the money while he worked for Cook's company, Great Dane Enterprises. His attorney has said he denies taking money without Cook's consent.
Erika McCauley's attorney did not immediately return a message Thursday.