"We're always hopeful that we can find her alive, but time is our enemy. So, we're trying to progress as quickly as we possibly can in this case," Sergent Kevin Perlich said.
Using drones, the police concentrated their search efforts in a field near Richland College, which is less than 3 kilometres from Ms Mathews home in Richardson. Her adoptive father Wesley Mathews told police he left her outside at 3 in the morning.
The Johnson County Sheriff's Officer and Mansfield Police Department were seen helping Richardson Police Department with the search for Ms Mathews in an undisclosed location.
Police said they conducted multiple searches in "areas of interest" they had developed during the course of the investigation, including fields, creeks and wooded areas. Cadaver dogs were later seen arriving at the scene to help with the search.
The police say the family's SUV disappeared for an hour on the morning the girl disappeared. Investigators are asking any neighbours with surveillance video of the vehicle to come forward.
A priest placed a sign outside the Mathews' family home calling on the girl's parents to "tell the truth." "We the community are never going to stop until we find Sherin," said Thomas Ambalevelil. Her parents both remain "uncooperative," according to police.
Child Protective Services took custody of their other biological daughter, who is four years old, shortly after their father Wesley Mathews was arrested.
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