Louisiana’s prison system routinely holds people weeks and months after they have completed their sentences, the U.S. Department of Justice alleged in a lawsuit filed Friday. The suit against the state of Louisiana follows a multiyear investigation into what federal officials say is a pattern of “systemic overdetention” that violates inmates’ rights and costs taxpayers millions of dollars a year.

DOJ alleges that since at least 2012, more than a quarter of the people due to be released from Louisiana prisons have instead been held past their release dates. DOJ warned Louisiana officials last year that the state could face a lawsuit if it didn’t fix the problems, but lawyers for the department say the state’s “marginal efforts” to address the issues were “inadequate” and showed a “deliberate indifference” to the constitutional rights of incarcerated individuals.

“(T)he right to individual liberty includes the right to be released from incarceration on time after the term set by the court has ended,” Assistant Attorney General Kristen Clarke said in a statement announcing the suit.

“To incarcerate people indefinitely … not only intrudes on individual liberty, but also erodes public confidence in the fair and just application of our laws.”

In a joint statement provided to The Associated Press, Louisiana Gov. Jeff Landry and state Attorney General Liz Murrill blamed the problem on the “failed criminal justice reforms” advanced by “the past administration.”

“This past year, we have taken significant action to keep Louisianans safe and ensure those who commit the crime, also do the time,” the statement reads. “The State of Louisiana is committed to preserving the constitutional rights of Louisiana citizens.”

The Republican state officials also characterized the effort as a last-ditch lawsuit by outgoing President Joe Biden, reasoning that the incoming administration of Donald Trump would not have allowed the case to be filed.

Advocates have repeatedly challenged the conditions in Louisiana’s prison system, which includes the country’s largest maximum-security prison, known as Angola, where incarcerated individuals toil under the blazing sun picking vegetables by hand at what was once a slave plantation.

___ Kate Payne is a corps member for The Associated Press/Report for America Statehouse News Initiative. Report for America is a nonprofit national service program that places journalists in local newsrooms to report on undercovered issues.