The weeklong search for a missing 6-year-old Georgia boy ended tragically Thursday afternoon when his body was found in a field not far from his home, police confirmed.

The body of Christopher Michael Barrios Jr. was found in a black garbage bag at about 4 p.m. EDT in a field near the Brunswick, Ga., airport by a Department of Natural Resources officer, police said.

Christopher had been missing since last Thursday.

Glynn County Police Chief Matt Doering said he expected to file murder charges against four people already in custody: George Edenfield, a 32-year-old convicted sex offender; his parents, David and Peggy Edenfield; and, family friend Donald Dale.

"We believe they did it," Doering said, adding that he knew the motive for the killing but would not reveal it to reporters.

Doering said he was the one who told Christopher's father the tragic news.

"That's the hardest time I've had to hold my composure," he said.

"It's a big relief, really, to know the boy is found, even though he's dead," Christopher's uncle, Carlos, told local FOX affiliate WAWS. "At least now he can get a proper burial."

Carlos Barrios said the body was found in a "pile of trash" and was covered in some type of bag.

"He wasn't trash, he was a good kid," Carlos Barrios said, adding that the family is "pretty torn up right now." He also thanked all the volunteers and authorities who helped in the search.

Police said four shovels were found during the investigation: One was found Monday night during a search of George Edenfield's home, while the other three were found Wednesday night around Dale's home, Doering told FOX affiliate WAWS.

The Edenfields and Dale had been providing investigators with false information and leads for several days, police said.

"My hopes jumped back up that he's alive and that we're gonna find our baby alive and he's gonna come back home," Christopher's grandmother, Sue Rodriguez, told FOX News just hours before the tragic news of her grandson's death surfaced.

"They haven't found no baby's body and as along as that's not so, I'm gonna continue to hope and pray that he's alive and that he's coming home."

George Edenfield's parents and Dale were arrested this week and charged with obstructing an officer, providing false information and concealing the death of another — meaning they gave leads to police about where Christopher's body was that never panned out. Charges will now be upgraded to homicide, police said.

"All that is under state law, if you told me you buried a body and you took me out there and you couldn’t produce the body ... then we charge you with that because you say you have knowledge of it," Glynn County Police Capt. Jim Nazzrie said. "It probably won't hold up in court but it's still a charge."

Doering said Thursday that even though many leads the Edenfields and Dale gave police didn't turn up a body, the clues still were somewhat helpful. The body was not found in any of the places the suspects revealed to police.

"Everywhere we searched, we found nothing we were supposed to find," Doering said. But "we were confident that to some degree, they were telling us the truth ... that kept us looking, kept us focused."

Asked whether she believed the Edenfields and Dale knew where Christopher was, Rodriguez earlier said she thinks the four are "playing like they're crazy" in leading frustrated police around to different spots only to come up empty in their search.

"I've begun thinking they are a little bit off but I think there's a lot playin' and this ain't no game," she said.

Investigators on Thursday searched another pond for the boy. Searchers had been combing the same general 5-square-mile area for a week in their search for Christopher.

"We hope we find him," Nazzrie told FOXNews.com Thursday before the news broke of Christopher's death. "I'm very hopeful we're going to find him alive ... you always have that hope that someone will be found alive."

Police searched a thicket of dense pines Wednesday night where Edenfield's father, David, and Dale told investigators they had buried the boy's body. They also searched a pond near the mobile home park in which both the Barrios and Edenfields live.

But hours of searching with high-tech gear failed to turn up any sign of the child. The search was suspended for the night around 10 p.m.

Police said Monday night was the last night the people in custody referred to Barrios as a child and not a body, WAWS reported. Investigators also began searching areas outside of Glynn County later this week. They said they also wanted to talk to other persons of interest.

In one interview, police said George Edenfield told them he knew where the boy was, but in another he said he didn’t know anything about his disappearance.

"The father and his friend basically confessed to burying little Christopher," Nazzrie told FOX News on Wednesday. "They took us to the area, several areas … for some reason they want to lie about it, they can’t remember where they buried the body or if they did bury the boy," he said.

"[George Edenfield] actually said that he had hurt the boy and his momma and then had moved the boy," Nazzrie said.

Christopher was last seen last Thursday night walking on a road not far from the homes of his father and grandmother, who live in a mobile home park about a half-mile from Interstate 95 just outside the port city of Brunswick on the Georgia coast.

On Monday, the Georgia Bureau of Investigation issued a Levi's Call, the state's equivalent of an Amber Alert.

FOXNews.com's Liza Porteus reported and wrote this story.

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