The District on Wednesday sued six Maryland parents, alleging that families sent their children to D.C. schools without paying the tuition required of students living outside the city. The lawsuits seek $700,000 in unpaid tuition and damages and potentially hundreds of thousands more in penalties.

“The message is important and clear. If you’re not a resident of D.C. and you seek to send your kids to D.C. schools, there is a legal process to apply and pay to send your kids,” D.C. Attorney General Karl A. Racine said in an interview Wednesday. “If you choose to instead lie and submit false information, then the office of the attorney general will conduct an investigation and, where substantiated, we will not hesitate to file suit.”

The District alleges in four separate lawsuits that the Maryland parents sent a total of 10 students to D.C. schools between 2007 and 2018 without paying tuition, which ranges from $10,000 to $14,000 a year. Schools attended by the children include Duke Ellington School of the Arts, Capitol Hill Montessori and McKinley Technology High School, according to a statement from Racine’s office.

Under D.C. law, authorities can seek triple the amount of tuition that parents avoided by using a fraudulent D.C. address, leading to hefty fines.

The lawsuits allege the parents “lied repeatedly in documents attesting to D.C. residency to avoid paying non-resident tuition” and that the parents used D.C. addresses belonging to other people and signed sworn statements that they lived in the District.

Named in the lawsuits are William H. Harrison and Cassandra V. Harrison of Brandywine; Ionosphere Torres of Oxon Hill; Shawn L. Clark and Erica P. Fowler of Hyattsville; and Donnise Wortham of Capitol Heights. Racine said his office was investigating dozens of additional cases of potential residency fraud.

William Harrison said in a phone interview the allegations that he and his wife defrauded the District were untrue and that they would challenge the lawsuit. Harrison said he and his wife had been separated and that their children lived with his wife in her District home when they attended D.C. schools.

“I’ve been battling DCPS and [the Office of the State Superintendent] on this for two years,” Harrison said. “This is a personal attack on us. It’s frivolous and we’re going to fight them.”

Attempts to reach Torres, Clark, Fowler and Wortham were unsuccessful.

Residency fraud has been an ongoing problem in D.C. schools, but residency status is often complicated, and it has been difficult for officials to nail cases shut. In May, a citywide investigation alleged that more than 30 percent of the students at Duke Ellington School of the Arts — more than 160 students — 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.

“I would never say that there are parents who haven’t misrepresented their residency,” Ellington’s chief executive, Tia Powell Harris, told The Washington Post in October. “But I think the extent to which that happens has been blown up.”

The Office of the State Superintendent of Education said it has increased efforts to identify and remove nonresident students. The office added two investigators and a director to monitor residency and “to make sure our students are given the seats they deserve in our classrooms.”

Tips regarding residency issues have increased “because the agency has put significant effort into increasing public awareness around the issue through campaigns and outreach that direct people to an anonymous tips hotline to express those concerns,” Fred Lewis, spokesman for the superintendent’s office, said in an email.

In May, Racine’s office filed lawsuits seeking more than $800,000 from four Maryland parents — including three who worked for the District government — alleging they had fraudulently enrolled their children in D.C. schools.

Racine said Wednesday his office receives 50 to 100 reports a year of potential fraud from the superintendent’s office and private individuals. “We know it’s a problem that continues,” he said. “It’s important that we investigate and bring these cases.”

Perry Stein contributed to this report.