Updated at 9 p.m. July 11: Revised to reflect that bail has been set for Sedrick Johnson.

A day after his disappearance triggered a statewide Amber Alert, 18-month-old Cedrick Jackson was found dead Thursday at a landfill and his caregiver’s boyfriend was arrested, police say.

Sedrick Johnson, 27, has been charged with injury to a child causing serious bodily injury and is being held in the Dallas County jail with bail set at $503,000. Other charges are pending, Dallas police Maj. Vincent Weddington said.

Johnson is the boyfriend of Crystal Jackson, who was caring for her nephew after CPS placed him in her custody. Police declined to comment when asked if Jackson was a suspect.

18-month-old Cedrick Jackson was last seen early Wednesday in Lake Highlands, authorities say. (Dallas Police Department)

The boy's mother, Dishundra Thomas, declined to comment when reached by phone Thursday morning.

Weddington said Johnson confessed to police that he had taken Cedrick and placed him in a dumpster in northeast Dallas. Detectives learned the dumpster had since been emptied at least twice at a landfill on the boundary between Garland and Rowlett.

He said the remains, thought to be Cedrick's, were found shortly after 11 a.m. Thursday at the C.M. Hinton Jr. Regional Landfill and Wood Recycling Facility. The coroner's office will confirm the identification and determine a cause of death.

"This is not the outcome we had hoped for, and we want to extend our deepest sympathies to the family at this time," Weddington said.

On Thursday morning, Jackson told WFAA-TV (Channel 8) that police informed her that her nephew had died.

"He's dead," Jackson told the station. "He's gone."

Johnson told police the boy had been swaddled in a blanket on the floor before he died, according to an arrest-warrant affidavit. He said Cedrick had been at the home since May 21, and was swaddled nightly to limit his movements because he’d once “made a mess” with ketchup packets.

Dr. Rachel Y. Moon, chair of the task force that authored the American Academy of Pediatrics's safe sleep recommendations, has recommended caregivers stop swaddling babies when they look like they're trying to roll over, around 2 months.

Johnson told police he unwrapped the child after he heard him making noises around 12:30 a.m. Cedrick began to throw up at that time and became unresponsive, he told police.

Johnson told police he gave the toddler CPR for more than 30 minutes. Cedrick was not moving, he said, although he could still detect a heartbeat. He then drove the child to a dumpster and placed his body inside, according to the affidavit.

Johnson previously pleaded guilty to a child abandonment charge in 2011 and was sentenced to four years of probation. He later violated that probation and was sentenced to eight months in state jail in 2016, according to court records.

Sedrick Johnson (Dallas County Sheriff's Department)

Child Protective Services had recently placed Cedrick with Jackson, his aunt.

State officials removed six children from Jackson's home Wednesday night, said Marissa Gonzales, a spokeswoman for Texas Department of Family and Protective Services. Two of the children were Jackson's, while four belonged to Johnson.

Maintenance workers at the apartment Thursday said they were repairing the front door of the unit where Cedrick lived, but they declined to say what had happened to the door. A window had also been broken at the apartment.

Around the same time Thursday morning, a KXAS-TV (NBC5) news helicopter spotted police at the landfill.

Around noon, search crews appeared to have found Cedrick and set up a red sunshade over the spot. Two searchers could be seen hugging each other.

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Officers responded to a call about the missing child shortly after 6 a.m. Wednesday. Jackson told police she had put the child to bed at 11 p.m. and woke up to find he was gone.

Another child at the home reported seeing a man who resembled Cedrick's step-grandfather take the boy away.

The step-grandfather was in custody on unrelated charges in Keller and was later transferred to Garland police, who declined to comment Thursday. Dallas police said the step-grandfather was not a person of interest.

Police described the case Wednesday as a "possible abduction" and said Cedrick, who went by C.J., could be in danger.

A regional Amber Alert was issued for Cedrick's disappearance shortly after noon Wednesday and was upgraded to a statewide alert that night, police said. That alert was discontinued shortly before noon Thursday, around the time the boy was found at the landfill.

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Police did not say why Cedrick was placed with his aunt, but Thomas, the child's mother, said it was temporary and not against her will.

"We just want our son back," Thomas said outside Dallas police headquarters Wednesday. "He's not even 2 years old yet. I just want him back home with me."

Thomas said she had suspicions about the aunt's story.

"As far as her version of the story, I really don't know how to wrap my head around it," Thomas said. "It just baffles me that a child can get taken in the middle of the night without anybody hearing anything, a child that was sleeping next to you in your bed."

Investigation timeline

Police said Cedrick was last seen around 12:30 a.m. Wednesday at his aunt's apartment in the 9700 block of Whitehurst Drive. Officers responded to a call about the missing child around 6:50 a.m., police records show.

Police first notified the public of the "possible abduction" in a blog post just before 12:30 p.m. Wednesday, then spoke at a news conference at 3 p.m., where they said a regional Amber Alert had been issued for Cedrick's disappearance.

A statewide Amber Alert went out about 9:30 p.m. Wednesday.

Police recovered the child's body around 11 a.m. Thursday in a landfill.

Staff writers Paul Cobler, Sarah Sarder and Emma Ruby contributed to this report.