Missing Texas girl Audrii Cunningham was found dead Tuesday afternoon.
The 11-year-old's body was found in the Trinity River near the US Highway 59 bridge in Livingston, Polk County Sheriff Byron Lyons confirmed during a Tuesday press conference.
"We will continue to process the evidence that has been gathered to ensure that there is justice for Audrii," Polk County Sheriff Byron Lyons said.
Polk County District Attorney Shelly Sitton said her office is preparing arrest warrants for Don Steven McDougal, 42, in connection with Cunningham's Feb. 15 disappearance. They are eyeing capital murder charges.
McDougal was arrested on Friday on unrelated charges of aggravated assault with a deadly weapon and gave him "several opportunities to cooperate" with their investigation into Audrii's disappearance, said Lt. Craig Cummings, spokesperson for the Texas Department of Public Safety in Southeast Texas.
"He was probably taking her to…the bus stop, and we do feel that he was the last person to see Audrii," Polk County Sheriff Byron Lyons said of McDougal during the Monday press conference, adding that there were "some occasions" when McDougal would take Audrii to the bus stop or even to school if she missed the bus.
Lyons urged the public not to "jump to conclusions" as his office works to build a strong criminal case.
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The 11-year-old girl should have gotten on her school bus on the morning of Feb. 15, when she was last seen at her residence in the 100 block of Lakeside Drive, in Polk County, Texas, but she never made it on the bus or to school that day, officials said.
McDougal lived in a camper behind the residence where Audrii lived with her father, grandparents and other family, Cummings said. Audrii's mother, Cassie Matthews, told FOX 26 Houston that she believed McDougal would babysit the 11-year-old girl while he was staying at her father's home.
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Investigators are trying to piece together a timeline of McDougal's movements on the morning of Feb. 15. McDougal agreed to show investigators "certain locations" after his arrest, Lyons said.
A statewide Amber Alert was issued on Feb. 16.
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Lyons said later that there is a "high probability" that a backpack located in a wooded area near the Livingston Dam belonged to Audrii.
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McDougal has an extensive criminal history dating back to the early 2000s. His charges range from enticement of a child in Brazoria County in 2008 to assault of a family member and evading arrest in Liberty County, among dozens of other crimes.
Investigators are asking the public to submit any video footage they may have of FM 3126 in Polk County between 6:30 a.m. and 9:30 a.m. on Feb. 15.
Authorities are offering a $10,000 reward for information that could help them convict the person responsible for Audrii's disappearance.
