Mother of Mystery Maine Boy Confesses to Killing Son and Dumping Him on Rural Road: Sources Julianne McCrery confessed to killing six-year-old son.

May 18, 2011  -- A Texas woman has confessed to killing and dumping her son's body along a rural road in Maine, sources told ABC News.

The 6-year-old boy, Camden Pierce Hughes, was dumped by Julianne McCrery. McCrery told police that she accidentally gave her son too much cough syrup, the sources said.

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.

The woman who is being questioned in connection with the case has been taken to a local hospital for a medical evaluation and has not been charged with a crime, said David Procopio, director of communications for Massachusetts State Police.

"She remains in the care and custody of Massachusetts State Police. ... I'm not confirming any ages and names," Procopio said at a press conference this afternoon. Procopio declined to identify the woman or the boy and referred reporters to the New Hampshire State Attorney's office. He also declined to say why New Hampshire authorities were in charge of the investigation.

A Massachusetts state trooper spotted McCrery this morning at a rest area near Chelmsford, Mass., 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," Procopio said.

The "lone occupant," McCrery, was in a blue Toyota Tacoma pickup truck, the same type of truck that authorities have been frantically 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 was taken into custody at the Concord State Police barracks.

State Police officials confirmed that they are questioning the woman in connection with the discovery of the boy's body, which was found fully clothed under a green fleece blanket on Dennett Road in South Berwick, Maine, on Saturday.

McCrery's ex-boyfriend told ABC affiliate WCVB that he never thought McCrery would hurt their son.

"She loved him dearly," Miller said. "He was a very nice little boy. He was real smart."

The mystery of who dumped the boy has 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.

Indeed, 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.

The death has been deemed suspicious, and investigators have not ruled out homicide.

ABC News' Marisa Bramwell contributed to this report.