Police say they believe 11-year-old Kaye-lea Plummer was killed at her home in Florida before her mother put her body in the truck.
"I can't even wrap my head around what even would have made [my wife] snap", Plummer told the station.
She said her daughter did not move, eat, drink or use the restroom in the two days it took for them to drive from Florida to West Virginia.
He told the television station he received a text from Newsome on Saturday saying she was bringing their daughter to Buffalo.
Plummer and Newsome had been separated since 2014, and he said that they didn't have a solid relationship, but they kept in contact. "Something pushed her over the edge and she snapped".More news: Officer shot, killed in Clinton Missouri
Newsome drove some 700 miles with her daughter's body in the auto, and planned to drive all the way to Buffalo, New York where the girl's father lives. Newsome and her daughter were found on a logging road about 150 feet from an embankment.
Barlow said a couple traveling on the same highway reported seeing Newsome remove a body from her vehicle and drag it over a hill.
The mother was jailed on $50,000 bail on the charges of concealing a body, while investigators search for evidence in Florida according to Action News.
Newsome was headed to NY to see Kay-Lea's father who spoke with Action News Jax reporter Russell Colburn, who said that he spoke with Newsome while she drove and she acted like everything was fine. Reports from West Virginia say Newsome confessed to killing and abusing Kaye-Lea.
Officials have not disclosed a cause of death, but West Virginia State Police Sgt.More news: Terror probe after blade incident at Eiffel Tower
"They just said she was found at the scene of an accident, but they don't believe my daughter died there", Plummer said.
Plummer described his wife as a "great mother" and "the only person I trusted with my child", and said he couldn't understand why she would have hurt their daughter. 'Something is very, very wrong.
Plummer said that when he found out about what happened he was at work. "She needs help. She really needs help".
The body of the deceased child was discovered Sunday after a auto wreck on a remote stretch of U.S. Route 250 in Pocahontas County just over a mile from the Virginia border.More news: He will need dialysis, says doctor