MILWAUKEE – In 2014, the Wisconsin Department of Public Instruction (DPI) created an online portal for parents of special needs students to report any discrimination their children might endure while attending private schools in the Milwaukee Parental Choice Program.

No complaints were ever filed.

MORE NEWS: From Classroom to Consulate Chef: Culinary Student Lands Dream Job at U.S. Embassy in Paris

So it’s no surprise to anyone that a federal investigation of alleged discrimination in the choice program has ended, with no enforcement action taken.

The Milwaukee Parental Choice Program, the oldest private school voucher program in the nation, allows lower- and middle-income students to leave Milwaukee Public Schools (MPS) and enroll in a participating private school.

Qualifying students are allowed to use a portion of their per-pupil state funding for tuition, with the balance going to MPS.

Opponents of the program, particularly within MPS, have long hoped to have the program disbanded. They question its constitutionality – particularly since most of the schools in the program are religious in nature – and argue that it takes crucial financial resources away from the academically-troubled MPS.

In 2011, when the debate over expansion of the program raged, opponents were able to seize on an issue.

They supported and publicized a complaint filed with the U.S. Department of Justice (DOJ) by Disability Rights Wisconsin and the American Civil Liberties Union, claiming that the schools in the Milwaukee program discriminated against special needs students by failing to provide adequate services.

MORE NEWS: Know These Before Moving From Cyprus To The UK

They did so in the knowledge that the private schools in the program receive fewer federal and state dollars than public schools, and receive no special funding for special needs services.

They suggested that the lack of services prevents special needs students from enrolling in the program.

But according to an estimate from the School Choice Demonstration Project, between 7.5 and 14.6 percent of the nearly 30,000 students in the program have disabilities that would probably qualify them for special services, according to School Choice Wisconsin.

That suggests that many students with various types of disabilities are happy to participate in the choice program, regardless of the level of special services offered.

The Wisconsin Institute for Law and Liberty has been monitoring the number of complaints received from the parents of special needs students through the special state portal. As of November that number was zero, according to the Journal Sentinel.

“You’d think if there was a large outcry of parents upset with the private schools we would be hearing it by now,” CJ Szafir, vice president for policy at the Wisconsin Institute for Law and Liberty, was quoted as saying by the Journal Sentinel.

Long periods have passed with little or no word about the status of the federal investigation, according to several media sources.

The DPI finally received a letter from the DOJ last month, announcing that the investigation is being closed with no action taken, according to the Milwaukee Journal Sentinel.

Many supporters of the voucher program suspect that the federal complaint was filed as an effort to cause legal trouble for the voucher program, and perhaps lead to its downfall.

“After four years, this secretive investigation has come to an end,” Jim Bender, President of School Choice Wisconsin, was quoted as saying in a prepared statement.

“The DOJ has now reaffirmed what the DPI stated all the way back in 2011 – there is no record of the school choice programs in Wisconsin discriminating against students with special needs.”