A Texas woman has been arrested and charged with second-degree murder in connection with the killing and dumping of her 6-year-old son's body along a Maine rural road, authorities said.
Julianne McCrery, 42, was arrested Wednesday on a Massachusetts fugitive-of-justice charge, according to a news release issued by authorities in three New England states.
"The fugitive from justice charge arose from an arrest warrant issued in the State of New Hampshire on the charge of second-degree murder," the release stated.
On Wednesday, sources told ABC News McCrery has confessed to killing and dumping her son's body.
The Irving, Texas, woman told police that she accidentally gave her 6-year-old son Camden Hughes too much cough syrup, the sources said.
Initial autopsy results indicate asphyxiation was Camden's cause of death but final results are pending.
McCrery is expected to be arraigned this morning in Concord District Court in Massachusetts.
McCrery was taken into custody at a Chelmsford, Mass., highway rest stop after a Massachusetts state trooper spotted her, police said.
"At 10:20 this morning, we received a call from a citizen who had seen prior coverage of this investigation. ... We responded with several troopers there and engaged ... the lone occupant of the vehicle, and that's why we're here now," David Procopio, director of communications for Massachusetts State Police said.
McCrery was in a blue Toyota Tacoma pickup truck, the same type of truck that authorities have been searching for since Camden's body was found Saturday.
She told a Massachusetts state trooper that she killed her son and was contemplating killing herself, sources told ABC News.
When the female trooper asked McCrery if she needed assistance, she responded: "I killed my son. I want to kill myself."
McCrery once wrote a book about how to fall asleep called "Goodnight, Sleep Tight." In her author's bio, she described herself as a former school bus driver and cement mixer.
Authorities discovered Camden's body fully clothed under a green fleece blanket on Dennett Road in South Berwick, Maine, on Saturday.
The mystery of who dumped the boy puzzled investigators. Nobody filed a missing persons report for the boy. A scan of missing persons databases turned up no leads.
"He was clean. His fingernails seemed clean and appropriate. He was a small kid, but I don't think he was undernourished. He's a very cute boy, and again, he was clothed well. The sneakers are virtually brand-new on him," Maine State Police Lt. Brian McDonough said Tuesday.
An eyewitness spotted a woman driving a truck with a Navy insignia embossed in or around the truck's license plate.
Police began alerting Navy Reserve centers and brought in the Naval Criminal Investigative Service to help in the search because of a hunch that someone with a military connection may have dumped the boy's body.
One of McCrery's sons serves in the Navy. His Facebook page shows that he works as a chef in the Navy.
Other facts that hinted at a military connection included the boy's clothing. Found fully clothed, the boy had on a gray-colored camouflage hooded sweatshirt and a navy blue T-shirt with "Aviator Series" displayed on the front, police said.
The State Police Computer Crimes Unit produced a computer-generated photo of the unidentified boy. The boy was 3 feet 8 inches tall and weighed 45 pounds. He had dirty blond hair and blue eyes. His baby teeth had yet to fall out.
ABC News' Marisa Bramwell contributed to this report.