Police follow-up on leads of missing teen as family pleads 'Elizabeth must be found' Elizabeth Thomas' family is "desperate" to find the teen and her former teacher.

 -- As police in Texas and Alabama followed-up Thursday on leads to locate Elizabeth Thomas -- the Tennessee high school student allegedly kidnapped by former teacher Tad Cummins -- her family issued a lengthy statement saying they are "desperate" for additional information to find the 15-year-old.

She has been missing since March 13.

"The last ten days have been the most difficult in the life of the Thomas family," the statement reads. "We humbly ask that you continue to pray as we do our best to cope with the emotional weight of Elizabeth's abduction."

Family releases letter amid ongoing AMBER Alert for daughter https://t.co/TJ0jzcA5pp

— WKRN (@WKRN) March 24, 2017

The family does not only ask for information that may result in finding Elizabeth, but they are also seeking details about any relationship between their daughter and Cummins.

"We are desperate for any information that might lead to our daughter," the family's statement reads. "The information that we need is not only from what people have seen and heard after Elizabeth's disappearance, but also from before. Facts about prior events, especially interaction between Elizabeth and Tad Cummins and statements made by both parties to third parties, may very well contain clues to lead to Elizabeth's return."

The family pleads, "Elizabeth must be found. Time is of the essence."

The family also urged the public not to place blame on school officials for the alleged relationship or how it was dealt with.

"We know that each teacher and administrator at Maury County Schools mourns as we do over this tragedy and wishes daily for Elizabeth's safe return," the family urged in the statement. "Whatever questions about how issues were handled when Elizabeth was in school are distant and secondary and, in many ways, distracting, to the core issue of finding her."

The family added, "It is important to the Thomas family to emphasize that none of the reports about possible mistakes made regarding Tad Cummins prior to Elizabeth's disappearance are relevant to what we are doing now ... Our focus should be on finding Elizabeth. Period."

Also on Thursday, police in Corpus Christi, Texas, were reviewing surveillance video from a convenience store after officials in Tennessee shared a tip that a vehicle matching the description of Cummins' car was spotted in the city's North Beach area, reported The Associated Press.

And in Alabama's Morgan County, the Sheriff's Department said Elizabeth and Cummins may have stayed at a motel in Decatur, reported ABC affiliate WAAY on Thursday.

Motels in Decatur were raised as a possibility after investigators from the Maury County Sheriff's Office visited Decatur last week to search for the pair.

Ashley Hitt, a manager of a local motel, told WAAY that she has asked her staff to be on alert, telling them "just in case you do see [Elizabeth and Cummins], definitely to let me know or to call the police and let them know."