For the fourth time in the past year, the District is accusing families from the Maryland suburbs of fraudulently claiming to live in the city so their children could attend D.C. public schools. And three of the seven adults named in lawsuits worked for the school system at the time of the alleged fraud.

The lawsuit is the latest sign that District officials are more stringently enforcing residency fraud laws, which require families attending a D.C. public school to pay tuition if they live outside of the city.

The families skirted paying the required tuition, and the city’s attorney general said he is seeking more than $700,000 in unpaid fees and penalties, according to the lawsuit.

This is the fourth batch of residency-fraud lawsuits the city has filed in D.C. Superior Court in the past year, collectively seeking more than $2.6 million in unpaid tuition and damages.

“Residency fraud not only cheats our taxpayers, but it also hurts District children who play by the rules, and frequently rely on the school lottery process to attend the schools of their choice,” D.C. Attorney General Karl A. Racine said in a statement. “Our office will continue to bring actions against any individuals who try to fraudulently take advantage of free schooling for District students.”

The District alleges in three lawsuits that the families collectively sent six children to city schools between 2009 and 2015 without paying tuition.

Schools attended by the children include the now-closed Potomac Preparatory Public Charter School, Maury Elementary, Shining Stars Montessori Academy Public Charter School, Noyes Education Campus and Phelps Architecture, Construction and Engineering High School. Annual tuition at the schools for students from outside the city ranges from $10,000 to $14,000.

Under D.C. law, authorities wanting redress from lawbreaking suburban parents can seek to triple the amount of tuition those parents avoided by using a fraudulent D.C. address.

Named in the lawsuits Wednesday are April and Nicholas Fennell, residents of Oxon Hill, Md.; Chantese Alston, a former resident of Capitol Heights, Md., and current resident of the District; James Alston, a resident of Oxon Hill; and Rasaki Shittu and Rashidat Shittu of Upper Marlboro, Md.

Asaki Shittu, identified as the sister of Rashidat Shittu and a former employee of Noyes Education Campus, was also named in a complaint. The lawsuit alleges that Asaki Shittu handled enrollment matters at the school and helped her sister fill out false forms claiming D.C. residency to send her child to the school.

April and Nicholas Fennell are employed by Imagine Hope Community Public Charter School as a front desk liaison and physical education teacher, according to the D.C. attorney general’s office.

The families could not immediately be reached for comment Wednesday.

Residency fraud has been an ongoing problem but came under increased scrutiny last year after a city investigation alleged that more than 30 percent of students at Duke Ellington School of the Arts — more than 160 teenagers — lived outside the city and were not paying tuition. But in October, administrators and parents at the school said the city had determined at least 90 of the accused students live in the District.

The Ellington investigation laid bare the complicated lives of students in an urban school system and the complexities that come with investigating residency fraud.

The D.C. Office of the Attorney General says it has dedicated additional resources to combating residency fraud over the past two years, including more investigators and attorneys.