LOS ANGELES (AP) — A college entrance exam policy aimed at helping students with disabilities was exploited to enable cheating in what is being described as the biggest school admissions scandal ever prosecuted by federal authorities, according to court papers.

At least 50 people were charged in the scheme, which included not only cheating on the admissions tests but also bribing coaches to gain admission for students into elite schools. Among the defendants were actresses Felicity Huffman and Lori Loughlin.

A federal affidavit made public Tuesday details allegations of test administrators being bribed “to allow a third party to facilitate cheating” on the ACT and SAT exams. The document says that in some cases, that involved providing answers, correcting answers after the fact or having someone else pose as the student to take the test.

The College Board, which runs the SAT, and ACT Inc. provide accommodations for students with medically documented disabilities that can include giving students extra time to complete the test or allowing them to take it alone under the supervision of a proctor.

Both organizations are now defending the integrity of their testing process.

The College Board said it has seen an increase in disabilities accommodations request in recent years as more students have opted to take its exams.

The court documents revealed how some wealthy families exploited the rite-of-passage exam that most high schoolers endure in order to apply for college admission. Clients paid $15,000 to $75,000 per test, according to the documents, “with the payments typically structured as purported donations” to a charity run by a cooperating witness.