Authorities in Tennessee found the girls and their step-father Wednesday morning in Smith County which is located about 30 miles east of Nashville.  Their step-father, Matthew Hess, was hit with child neglect and abuse charges Wednesday afternoon as Iredell County authorities evaluated the case.

According to Sergeant Stacey Heatherly with the Tennessee Highway Patrol, the girls and their step-father were located around 9:16 a.m. on westbound I-40 near the 256 mile marker.

A driver recognized the Green Ford Explorer and alerted authorities who then followed the vehicle and pulled Hess over.  He is being held at the Smith County Sheriff's Office.

Keara Hess is pregnant and only 12 years old.  Her sister, Sierra, is 11 years old.  Both were taken to a hospital to be examined, said Lt. Julie Gibson with the Iredell County Sheriff's Office. 

"Keara is still pregnant and we are getting her doctor in connection with Tennessee authorities," Gibson said.

WBTV spoke with the girls' mother, Janette Hess, who was very excited to learn her daughters were OK.

"I'm very excited, very happy, I want to thank everyone for all the prayers," she said. 

 Iredell County Sheriff's Office talked to the district attorney after the three were found and decided to file misdemeanor charges of one count of child abuse and one count of child neglect against Matthew Hess, Gibson said. Authorities had been weighing charges based on the lack of adequate care for the pregnant daughter.

The search had been on for nearly a full week, but late Tuesday night, authorities stepped up the search by activating an official Amber Alert after they said the trio might be headed to Fayetteville or Tennessee.

Janette Hess said Keara and Sierra vanished with their stepfather on Thursday, Sept. 24.  Hess said she hadn't seen her daughters since they went to bed on Wednesday, Sept 23 around 9 p.m.

She said her estranged husband left a note the next day indicating that he left early to get some school supplies and he was taking his daughters to school. 

When Keara didn't show up for her doctor's appointment on Sept. 24, Janette Hess became suspicious and became worried.

"It's been a nightmare, I've been living in a nightmare," Hess said at the time.

Following the girls' disappearance, the Iredell County Sheriff's Office entered Matthew Hess and the two girls into NCIC.  The children were also listed on the Center for Missing and Exploited Children website. 

An Amber Alert wasn't issued until Tuesday night because the girls were with Hess, officials said.  Since he is a legal guardian, the circumstances surrounding the girls' disappearance did not meet the criteria of a missing child.  Tuesday night, however, officials changed course and issued an Amber Alert.

Gibson said the decision to activate an Amber Alert was made after "serious discussions" with the pregnant teen's physician.

"Due to the fact that Keara was supposed to be seen on Thursday, Sept. 24 for a medical procedure that was very important, we are now worried that with the passage of time, her health could be at greater risk," Gibson said Tuesday night.

She went on to say the sheriff's office did not think the two girls were abducted since Matthew Hess is Keara's custodial father. 

The sheriff's office said they just wanted to make sure Keara received the medical care she needs. 

"We are very worried about her and her unborn child," Gibson said Tuesday night.

Earlier this week, the sheriff's office said there was the possibility that Hess or the girls packed items for the purpose of having "an intended stay away from home." 

Some of the girls' clothing and other things were missing which they very likely would have taken on a trip, Gibson said.

Earlier this week, the sheriff's office asked other law enforcement agencies in other states to check their state parks, homeless shelters, camping areas, hotels and rest areas in case they spotted Hess and the girls.

The sheriff's office also said Hess has not broken any laws and Gibson said, "There are no warrants for Mr. Hess' arrest." 

He is their legal guardian and in North Carolina, a parent or guardian has the right to take their child whenever they want outside the state. 

Hess has been married to the girls' mother for 11 years.  For now, the sheriff's office said it has no evidence to suggest that he has ever harmed the girls.

Keara was due to have a medical procedure on the day in which she disappeared.  This procedure was very important for Keara to have, Gibson said.   

Keara never indicated that her stepfather was the father of the child, the sheriff's office said.  Based on information from the pregnant teen's mother, the father of the child is young person closer to Keara's age, Gibson said.  The mother told authorities her daughter named a particular individual as the father of the baby.

Keara got pregnant when she, her sister and Matthew Hess lived in Lincoln County.  At the time, Matthew and Janette Hess were separated.