State Police Sgt. Herby Barlow told the newspaper that it was obvious the girl did not die from injuries in the accident.
"I can't even wrap my head around what even would have made (my wife) snap", Plummer said.
There is no confirmation on a cause of death, but foul play is suspected and more arrests could be forthcoming in Florida, police said.
The West Virginia Highway Patrol reports that Newsome stated she had picked up her daughter, Kaye-lea Plummer, on Friday. There they also discovered the body of a dead child, who is reported to be Newsome's 11-year-old daughter.
The Pocahontas Times reported that a couple from New York City said they saw Newsome, 37, remove a body from the vehicle and drag it over the hill.
"Something pushed her over the edge and she snapped", he told News 4 Jax.
West Virginia State Police say witnesses pointed them toward the body which they observed Newsome remove from the vehicle soon after the accident in Pocahontas County. She and her daughter, Kaye-lea Plummer, were traveling from Jacksonville, Fl to Buffalo, NY when Newsome lost control of the vehicle in West Virginia. Now Newsome has been charged with concealment of a deceased human body, arraigned Monday afternoon in a West Virginia court, according to police. The couple married in 2007 and separated in 2009. The child was found about 150 feet over an embankment near the accident scene.
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Jemma reacted: "Now the pretty girl comes out with the naughty words, I thought you were a little sweet innocent girl". They continued: "She is finding it tough living with so many other people because she usually lives alone".
Plummer said Newsome did get his daughter an internet phone so they could talk.
Media reports from West Virginia said Newsome was on her way to Buffalo with the child's body Sunday morning when her vehicle struck a guard rail on Allegheny Mountain, a mile and a half west of the Virginia border.
Plummer said he received a text from Newsome Sunday night saying she was bringing his daughter to him in Buffalo.
Plummer says he hasn't heard from law enforcement or police since Sunday.
"If she hadn't been discovered [by the couple] I wouldn't have known about the child", Barlow added.
'We didn't always agree on everything, but she was a great mother. "I don't know how this could have happened", Plummer said.