Authorities said three other parents, identified as David Sidoo, 59, of Vancouver, Canada; Gregory Colburn, 61, of Palo Alto, California; and Amy Colburn, 59, also of Palo Alto; were previously indicted in connection with the scheme.
News of the indictment came one day after authorities announced 13 parents, including actress Felicity Huffman, planned to plead guilty to charges leveled at them in connection to the case.
>> Felicity Huffman, 13 others to plead guilty in college admissions bribery scheme
Authorities charged 50 people last month as part of the admissions scheme. At least nine college athletic coaches have been charged as part of the investigation, dubbed Operation Varsity Blues, authorities said.
Officials have said Singer has pleaded guilty and is cooperating with investigators. Former Yale women's soccer coach Rudy Meredith has also pleaded guilty.
Several coaches have pleaded not guilty, including tennis coach Gordon Ernst, who is accused of accepting $2.7 million in bribes to designate at least 12 applicants as recruits to Georgetown University.
The Associated Press contributed to this report.