Adkins took three polygraph exams. The first two times, he walked out of the room before the test was completed. The third time, he was found to be deceptive during the first part of the exam. During the second stage of the exam, Adkins revealed that Hailey might be in Scurry County, Texas. Investigators deemed him to be telling the truth. When pressed about a more precise location for the girl, Adkins refused to complete the test, according to the affidavit.
Kampfer said that investigators have searched Scurry County.
Investigators said that Adkins has given contradictory statements about the day Hailey disappeared.
Adkins also told investigators that he was fired from his job the day Hailey disappeared. Adkins worked for a company that does oil well casing and logging. His boss, however, told investigators that he wasn't fired, but abruptly left work minutes after showing up, according to the affidavit.
Adkins told investigators that he drove straight to his mother's home in Big Spring, Texas. Cell phone records show Adkins making calls from Dunn's home between 6:35 a.m. until 6:56 a.m., the court papers state.
Dunn left for work as a receptionist at a hospital at 6:20 a.m.
"According to all reports, Hailey Dunn would have been alone in the residence during this time period," the affidavit said.
Adkins eventually went to the home of his mother and used her computer. That computer has been taken as evidence, the affidavit said.
On the evening of Hailey's disappearance, Dunn and Adkins reportedly withdrew money from two banks to buy drugs, according to the affidavit.
There are also claims that the couple had a New Year's party, just days after the 13-year-old girl disappeared, according to the affidavit.
Dunn denied that, telling the Associated Press that just a few friends came over for drinks.
Dunn told the Associated Press that she had nothing to do with her daughter's disappearance. She said that she asked Adkins to move out Jan. 5.
"If investigators can't rule him out, I can't either," Dunn told the AP. "I'm unsure at this point."
ABC Affiliate KTXS and the Associated Press contributed to this report.