Federal charges were filed Thursday against Terry Allen Miles. He is the man who allegedly took two sisters from their Round Rock home last week.
Miles is also a person of interest in their mother's death.
According to the federal complaint against Miles, Tonya Bates died from blunt force trauma.
Late Thursday afternoon, he appeared before a federal judge in Denver.
A Las Animas County Deputy made the Wednesday evening traffic stop that ended the search for the two Round Rock sisters. The Deputy followed this gray sedan for several miles before back up could arrive, according to Undersheriff Derek Navarette.
"I was listening to the whole traffic stop go down, and I wasn't able to be there, so it was tough not to be there, and be listening and hoping everything went well, because it could have been really bad," Undersheriff Navarette.
Store surveillance image, obtained by authorities, showed Terry Allen Miles and the sisters were in Colorado buying camping gear, at least a full day before the body of Tonya Bates was found by police in their Round Rock duplex on New Year's Eve.
A phone belonging to one of the girls was located at the store in the town of Trinidad.
Investigators say a text message had been sent earlier from one of the girls to Tonya Bates' phone and it apparently helped authorities track the three to Colorado.
"I know we had been looking over the weekend, Sunday, Monday of this week for other tips we had been getting, but none of them turned out to be the suspect or the girls," Undersheriff Navarette.
One tip paid off. It lead a Deputy to a remote camp ground located between Trinidad and the resort town of Cuchara. The Undersheriff doesn't know how long Miles and the girls had been there.
"I know the FBI is sending a team up to that campsite today to process anything that may have been involved. but we didn't get up there to identify anything for them because we were more concerned about getting the vehicle stopped," Undersheriff Navarette.
The FBI took Miles into custody after he was brought into the county jail. Detectives with the Round Rock Police Department flew to Colorado Thursday morning to interview Miles.
Police Chief Allen Banks, when announcing the rescue Wednesday night, made it clear the investigation is far from over. "Obviously we still have a lot of work to do in regards to this case, we still have a lot of questions to be answered, hopefully we can have those questions answered," said Chief Banks.
It's believed the girls are in the custody of CPS caseworkers, who will try to learn more about the alleged abduction, according to Chief Banks. "They will have the opportunity to spend time with these girls will have an opportunity hopefully to question these girls and determined that at a later point we were just very happy that they're safe unharmed and will be able to return them home to their families," said Chief Banks.