On Saturday afternoon, authorities said 42-year-old Don Steven McDougal was arrested on an unrelated charge.
Earlier, DPS posted on X, formerly known as Twitter, that authorities are searching for a 2003 dark blue Chevrolet Suburban as a vehicle of interest.
Troopers said the Suburban belongs to McDougal and are offering a $7,000 reward for more information on Audrii's disappearance.
Investigators didn't specify if Audrii was last seen with McDougal and added that there are multiple persons of interest.
Authorities said they searched several locations on Friday and Saturday but have not found the 11-year-old.
Audrii's mother, Cassie Matthews, spoke with our sister station, ABC13 Eyewitness News in Houston, on Friday, saying she was told investigators found a backpack near the Lake Livingston Dam, but there are no signs of her.
DPS confirmed on Saturday that the backpack belongs to Audrii.
2003 Chevrolet Suburban wanted in 11-year-old's disappearance
Audrii was last seen around 7 a.m. Thursday on Lakeside Drive, not far from the home she shares with her father.
Neighbors say they usually see her walking to the bus stop with a dog, but that doesn't appear to have happened Thursday.
"She was allegedly dropped off at her bus stop, and later on, we come to learn that she never even made it on the bus," Matthews said.
"There's additional information out there. We're just not releasing it. That's what the investigators are using to follow up on," Lt. Craig Cummings with the Texas Department of Public Safety said.
Cummings asked anyone who has information about Audrii's whereabouts to contact the Polk County Sheriff's Office at 936-327-6810.