D.C. officials are looking into allegations that students at Excel Academy Public Charter School were enrolled despite not meeting city residency requirements, according to people familiar with the investigation.

Because students at the city’s public charters and traditional public schools must live in the District to attend — and receive an education funded with thousands of dollars in taxpayer money — enrolling from outside the city’s borders could be considered residency fraud.

One Excel school administrator, Lela Johnson, has admitted to enrolling her daughter at the school for three years while her family lived in Upper Marlboro, Md., according to a settlement agreement reached with the Office of the State Superintendent of Education in early October and obtained by The Washington Post. Johnson, whose responsibilities included overseeing enrollment at the all-girls school in Ward 8, agreed to pay the D.C. Treasurer $24,000 in back tuition.

Reached by phone Monday evening, Johnson said she still is employed at the school and declined to comment further. A spokesman for OSSE declined to comment.

Scott Pearson, executive director of the D.C. Public Charter School Board, said the settlement agreement with Johnson was “the first formal determination . . . after a whole summer of discussions about residency issues at the school.”

He said that the board got “several tips” about problems at Excel, tips the board passed along to the school’s board of trustees and to OSSE. One of the pieces of information was an outside audit of the school’s enrollment records showing widespread issues with residency verification. The audit was conducted by an outside consultant hired by the school’s former chief executive.

A copy of the audit, obtained by The Post, showed that just 196 of the 618 students enrolled at the school were in compliance with OSSE guidelines for residency verification. No documentation to verify residency was provided for 356 students, and 65 student files had residency documents that were out of compliance with OSSE guidelines, such as pay stubs that showed tax withholding in Maryland or utility bills or lease agreements that were provided without a corresponding receipt or canceled check.

On Monday night, the charter board asked Deborah Lockhart, chair of Excel’s board of trustees, to speak at the board’s meeting “to provide us with assurance that the school was going to be running a clean enrollment operation,” Pearson said.

Lockhart told the board that the school is working to improve its “enrollment issues.” The school hired an accounting firm to analyze what happened, she said, and hired another firm to review documents and get the school ready for the annual enrollment audit this fall. She said that the school plans to terminate anyone who is found guilty of fraud.

“Obviously, this is something for the next four or five years, we will always have to monitor very closely,” she said.

By law, schools are expected to maintain a residency verification form for each student, along with copies of documents proving residency. Excel Academy enrolls about 730 girls in pre-kindergarten through sixth grade, most of whom are low-income and African American.

The issue of nonresidents enrolling in D.C. public schools has become increasingly charged as the city has expanded access to publicly-funded preschool programs and poured millions of dollars into renovations. Parents talk of sitting on wait lists for schools while they see drivers with Maryland plates lining up to drop off their children.

Charter and traditional schools compete for students, and enrollment numbers drive school budgets. Charter schools are funded primarily through their per-pupil allotment. In fiscal year 2015, that amounts to about $9,500 per student in grades 1 through 5, and more than $12,000 for kindergarten or preschoolers. Schools receive extra funds for children considered at risk or who qualify for special education services.

The responsibility for investigating residency fraud originally was left to individual charter schools, but the charter board took it on during the 2012-2013 school year and quickly realized it was complex and labor-intensive, Pearson said. The board then transferred the responsibility to OSSE, which maintains a hotline for tips and hires private investigators to track down where students actually reside.

There were 36 investigations opened in the 2013-2014 school year, OSSE said. Fifteen of those cases have been closed, including six involving students that were found to be nonresidents. This school year, OSSE has received 14 tips. The D.C. public schools system conducts its own residency investigations. For the 2013-2014 school year, there were a total of 112 cases, with 81 closed.

Pearson said many suspected cases of residency fraud do not prove to be clear in a city with high mobility and children living with divorced parents or in other complex family situations.

Excel has undergone tremendous upheaval since the summer. The founder and at least two other school administrators lost their jobs.

Nikki Stewart, who was chief academic officer at the school, is pursuing a retaliation claim. She notified the board in July that she was reporting two cases of alleged residency fraud involving school officials, including Johnson. Five weeks later she was terminated.

Johnson was given a new position — executive principal – while her residency investigation was pending.

At the board meeting Monday, Lockhart said the school’s trustees decided to replace the top leadership of the school with interim leaders for reasons including low retention rates and low morale that was “manifested by poor management of the instructional and administrative staff.”

Correction: An earlier version of this story incorrectly reported the school year that the D.C. Public Charter School Board took over investigations of residency fraud. The board took over such investigations in the 2012-2013 school year. The story has been updated.