We can't believe it has been more than twenty years since Mary Kay Letourneau was jailed for starting a sexual relationship with her then-underage student, Vili Fualaau — and we just learned new interesting information about the case.

While Vili recently filed for separation, Barbara Walters Presents American Scandals taught us how Mary Kay would communicate with her lover while in prison.

MORE: Mary Kay Letourneau’s First Husband Has Found Happiness in His Post-Scandal Life

“Mary stayed in touch with Vili in a lot of different ways. One way was to send out messages in the milk bottles that she was — [producing] milk in prison for her babies, so she put little notes in the caps and they went out,” case expert Gregg Olsen explained. “She sent audiotapes out. She had prisoners make phone calls for her because she could not contact him [Fualaau] directly.”

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The controversial couple wed in 2005 and they have two children together, daughters Audrey and Georgia. Sources close to the situation have allegedly been blindsided by the demise of their relationship. Mary Kay filed court documents to have the case dismissed, while Vili has confessed this was allegedly done in hopes to benefit his “Cigaweed” business.

MORE: One Time, Mary Kay Letourneau Hosted a "Hot Teacher" Party With Vili Fualaau

“There is a piece of paper that is filed but that doesn’t depict what is going on. Be patient. It’s not serious as people think it is… Maybe we’re sleeping in different rooms. The paperwork that is filed doesn’t have all that information,” he previously told Radar Online.

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“I can’t even imagine them getting divorced. With his personality and her personality, they are not going to do anything to harm those children. They are always going to be friends. There is nothing that is going to separate them as friends forever,” family friend Lydia Edgmon told People.

Their pal David Gehrke agreed, adding, "They loved each other. They were devoted to each other. They had children together, and raised those children.”

You can watch Barbara Walters Presents American Scandals on Investigation Discovery GO.