A hearing was set for Monday in the case of missing Tennessee student Elizabeth Thomas. The 15-year-old's family has begged for anyone with information about her disappearance to come forward. Her father, Anthony Thomas, requested the deposition of at least two witnesses who he believed might have information that could help him find his daughter.  

Thomas filed a petition in court Thursday requesting the deposition of anyone who might have information about his daughter and Tad Cummins, the 50-year-old teacher believed to have kidnapped her.

Read: Elizabeth Thomas Knew Something Bad Would Happen Before She Disappeared

"The family cannot simply wait for information to trickle in," Jason Whatley, the attorney representing Anthony Thomas, told ABC News Thursday. "This petition will hopefully bring a fresh light into the disappearance of Elizabeth."

Elizabeth has been missing since Mar. 13 when she left her family's home for a restaurant and never returned. The girl told her brother that if she wasn't home by 6 p.m., he should contact police. Police believe she was abducted by her former teacher, Tad Cummins. The school had been investigating the relationship between Cummins and Elizabeth after an unidentified student saw them kissing in his classroom.

Since the pair disappeared, they have been spotted only once. Police confirmed the two were seen on security footage shopping in an Oklahoma City Walmart two days after Elizabeth was officially reported missing. Since then, there has been virtually no trace of the two. Police cautioned the public that this was not a romantic situation.

Read: Police Confirm Sighting Of Elizabeth Thomas And Tad Cummins 

"She is 15, a child. He is 50, a grown man. She's a high school freshman. He's a former teacher. This is, and was, not a romance," Tennessee Bureau of Investigation director Mark Gwynn told reporters. "This was manipulation solely to benefit Tad Cummins. This is not a fairy tale. This is a case of kidnapping." 

In the petition filed Thursday, Elizabeth's father said he believed his daughter was coerced and intimidated by Cummins and that the teacher threatened her with repercussions at school if she didn't join him for a meal. He also said Elizabeth told some of her peers that she was "in over her head" and scared of Cummins. Anthony Thomas said Elizabeth also hid from Cummins when he repeatedly tried to visit her at work and asked her co-workers to say she was not there. 

The petition also asserted that Cummins told Thomas that the school's investigation of the "kissing incident" had ruined his career, leading her to feel guilty about the situation. Cummins, taking advantage of her guilt, it stated, said the best option would be for them to leave together.