A South Carolina man will be charged with murder in the deaths of his five children – who were ages 1 to 8 – after their bodies were found wrapped in garbage bags off a two-lane highway in Alabama, authorities say.

Acting Sheriff Lewis McCarty of Lexington County said Wednesday at a news conference that Timothy Ray Jones Jr., 32, would be charged with five counts of murder when he arrives in South Carolina. Jones is currently being held in Mississippi.

Authorities in South Carolina and Mississippi said that Jones has already been charged with child neglect.

McCarty said authorities believe that Jones killed the five children at the same time, but he did not say specifically why he thought that. He said authorities are not sure of the motive for the killings, but officials believe Jones acted alone, with no one's help.

"They were wonderful. They were happy," Jones' stepmother, Julie Jones of Amory, Mississippi, told The Associated Press by phone Wednesday. She identified herself as Jones' stepmother.

"I'm sure everybody wants to know the answers," Jones' father, Timothy Jones Sr., said. He said he was working on a statement about his son's arrest and the death of his grandchildren. "It's just a terrible tragedy."

Autopsies have been set up to begin Thursday, although McCarty said he's unsure when they will be finished, and officials won't comment on any causes of death until then.

McCarty added that the children's mother, Jones' ex-wife, is in shock and distraught. The children were reported missing by their mother on Sept. 3, authorities said.

"This is a very tragic situation," Wilcox County (Ala.) District Attorney Michael Jackson said. "These kids' lives were snuffed out before they had a chance to enjoy life. Justice will be served."

Jackson said Jones is suspected of killing the children in South Carolina before taking their bodies to Alabama.

An Alabama Department of Public Safety spokesman told the Associated Press that Jones led police to the site near the town of Camden where the bodies were found.

On Wednesday morning, the dirt road where the bodies had been located — an isolated area between the Alabama towns of Pine Apple and Oak Hill, about 25 miles west of an Interstate 65 exit — was abandoned. Investigators had worked late into the night using flood lights, but there was no longer any sign of vehicles or people. Boot prints and tire tracks were especially prevalent around a pile of dead trees atop a sandy soil hilltop, guarded from view by the two-lane highway.

Jones was detained in Smith County on Saturday after being stopped at a motor vehicle checkpoint near Raleigh, Mississippi, and charged with drunken driving, Smith County Sheriff Charlie Crumpton said in a news release.

Crumpton said Jones became agitated when a deputy questioned him about an odor of chemicals coming from the Cadillac Escalade he was driving. The deputy found what were believed to be chemicals used to manufacture methamphetamine and a substance believed to be the street drug Spice, a form of synthetic marijuana, Crumpton said. A sheriff's office investigator was called and found what appeared to be bleach, muriatic acid, blood and possible body fluids, he said.

During a background check, police discovered that Jones was wanted in South Carolina "regarding a welfare concern of his children," who were on a national missing persons list, the Mississippi Bureau of Investigation said in a statement.

Investigators from several departments and the FBI started looking for the missing children on Monday, Crumpton said. He said the children's decomposed bodies were found in individual plastic garbage bags.

Jarrett told a news conference that authorities were not sure why Jones drove through Alabama.

Jones had joint custody of the children and is divorced from their mother, police said. They said he told neighbors that he and the children were moving to another state.

Marlene Hyder and her husband, Johnny Hyder, said Jones and his wife moved into a house next to them about seven years ago in Batesburg-Leesville, South Carolina, 25 miles west of Columbia. They said Jones told them he worked in computers. Two years ago, the wife moved in with a male neighbor and Tim Jones moved away with the children, the Hyders said.

Johnny Hyder said the children were often dressed in dirty clothes and were seen home at all hours of the day because Tim Jones had said he didn't believe in the public schools. Hyder said Jones was constantly looking for a reason to argue and often threatened to call the police. He said Jones approached him with a gun on his hip one day and was angry about something, but Hyder couldn't remember what it was. When Hyder said he was going to call police, he said Jones told him it was only a BB gun.

"It wasn't a BB gun," Hyder said. "It was a real gun. I know what one looks like, but I didn't want to cause any more trouble."

Marlene Hyder said Jones threatened to kill one of their dogs when it briefly went onto his property.

"He was a nut," she said.

Marlene Hyder said she also remembered a day when one of the Jones' younger children came over to the Hyders' house and tried to drink out of one of their outdoor spigots. He was dirty and disheveled and ran back to his house when she tried to speak to him, she said.

A "no trespassing" sign was posted near the driveway of a house where the Hyders said Tim Jones' ex-wife still lived with the other neighbor. Several people were seen walking around the yard, but none responded to questions from a reporter.

The Associated Press contributed to this report.