SAN PABLO -- Seven months before police began investigating financial aid fraud at Contra Costa College, campus administrators grew suspicious of the scam's ringleader but said they did not have enough evidence to bring their concerns to police, according to court papers released this week.

The head of the college's financial aid department did notify the U.S. Department of Education about the "red flags," but that didn't stop 45-year-old Yvette Hummel, who pleaded guilty to her role in an elaborate scam to bilk the college out of $109,000 in Pell Grant money.

Nearly two dozen people, none of whom is affiliated with the college, face charges related to a "Pell running" scam -- a widespread form of fraud in which people apply for financial aid money to attend college but never go to class.

Hummel first came across a financial aid office worker's radar in spring 2011, when the worker noticed Hummel visiting the college's financial aid office with different students and asking for their financial aid status. Suspicion grew when workers realized Hummel was sharing an address with at least one of those students, according to a police report.

In a subsequent meeting in June 2011 with interim Dean of Students Vicki Ferguson, Hummel admitted to running a business and charging a fee for helping students apply for financial aid but described herself as a "good Samaritan" in doing so, according to records.

Financial Aid Director Viviane LaMothe contacted the inspector general of the Department of Education and had Hummel's information flagged so Contra Costa College financial aid workers would be aware if she returned.

She never did, according to court papers. Instead, she used online registration on computers off campus to enroll others in classes and never used her name, according to prosecutors. In all, investigators say Hummel enrolled 53 "straw students" during the fall 2011 and spring 2012 semesters, but they never attended class. Some never set foot on the San Pablo campus, investigators say.

Hummel took a 25 percent cut of the financial aid checks, which typically were $2,775 a semester, authorities said.

The scam was uncovered in January 2012, when one of the 53, who wanted to attend class and had trouble getting her records and applying, brought her concerns to school officials, who called police.

Ferguson did not return a call for comment. LaMothe couldn't be reached because she retired from the college in March after 24 years in the district. District spokesman Tim Leong said her retirement was not related to the investigation into the financial aid scam.

Criminal charges were filed in November, and authorities are still searching for eight suspects. Four of the suspects, including Hummel and her 54-year-old boyfriend, David Murphy, have taken plea deals that include jail time and probation.

Also in the police report are summaries of interviews with drama department instructors about 28 "straw students" who received grades without ever attending class. None of the five instructors interviewed recognized names or photos of the fraudulent students, nor did they know how they could have received grades, though they offered theories that the computer system could have been hacked.

The class, which has open enrollment and allows students to sign up throughout the semester, was responsible for three public performances that fall. Grading is done by the instructors collectively, they told police, and based on hours of attendance and students' attitude.

One of the students earned an "A" in the class, meaning the student would have had to spend between 160 and 200 hours in class. That student enrolled in the class about a month before the semester ended.

All instructors were cleared of any criminal wrongdoing.

Drama department chairman Clay David, who was later placed on administrative leave, filed a claim against the college alleging he was punished for speaking out against homophobia on campus. He no longer works at the college, and district officials will not say why he was placed on leave.

Contact David DeBolt at 925-943-8048. Follow him at Twitter.com/daviddebolt.