(CNN) Federal prosecutors are accusing some parents, including actress Lori Loughlin, of withholding evidence in the college admissions scam case despite requests to turn it in.

Loughlin and her husband, Mossimo Giannulli, allegedly paid $500,000 to the scheme's mastermind to have their daughters pose as University of Southern California athletes. They were also accused of bribing USC employees to get their daughters admitted.

Last year, the couple pleaded not guilty to charges of conspiracy to commit fraud, conspiracy to commit money laundering and bribery.

In a court filing Friday, federal prosecutors say a majority of parents haven't submitted their discovery materials. With the exception of Bill McGlashan and Robert Zangrillo, all the other parents have not provided any discovery to the government, according to the joint status report filed Friday. Discovery material is information and evidence that both sides of the case share with each other prior to trial.

"The government disagrees with the defendants' assertion that it is premature to provide their own discovery," the filing states. "The government contends that it has complied with its discovery obligations and continues to comply with them."

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