A 20-day-old baby boy was found dead in a California swamp on Wednesday after he was reported missing and his mother was found hysterical in a case that has investigators scrambling for answers.

Justice Rees was found Wednesday at around 10 a.m. on the bank of a remote slough by the Sacramento River in Yolo County, sheriffs told KGO. Searchers had to cut through a brush to reach the infant's body from the slough in the Knight's Landing community.

"This is mind-blowing," Randy Green, Justice's grandfather, told KCRA. "It's like a dream I'm still trying to wake up from."

While an autopsy is underway to determine a cause of death, Yolo County investigators are trying to construct a timeline of events since Justice and his mother were reported missing from where they live in Woodland on Monday.

Samantha Green, the baby's 23-year-old mother, was found Tuesday evening not far from where her infant was found in Knight's Landing. She had scratches on her body, was "crying and hysterical," deputies told KCRA.   

Green reportedly said she and Justice were abducted, but police do not know how they ended up in the swamp and Green was unable to tell police where she and her son had been.

A resident near Ridge Cut Slough, where baby Justice was found, told Fox 40 on Tuesday he saw Green in the area calling for help.

"All she can remember was that she was abducted here in town," Richard Vallasenior told the station. "She was pretty bruised up and scratched up. She says she's been out there for about two days."

Green was treated at Woodland Memorial Hospital and later discharged. Her family says they have not been able to get in touch with her.

Foul play is not suspected in the baby's death and Green is not considered a suspect. But investigators are combing over every aspect of the mother's story to determine what happened.

"He was a good boy. He was only here for three weeks, less than three weeks, he never had a chance," Randy Green told KGO.