The missing persons case has since turned into a murder investigation. The Apple Valley Police Department and the San Bernardino County Sheriff’s Department announced Saturday that Duke’s mother, Jakee Raquel Contreras, 29, and her twin sister, Jennifer Rachel Contreras, have been booked on suspicion of murder.
According to a joint news release, deputies and Apple Valley police officers went to the boy's home just after 10 p.m. Thursday to check on his welfare. At that time, Jakee Contreras told them her son had been missing for two weeks.
KTLA reported that Duke lives at the home with his mother, father and aunt. The news station reported that the boy's father, who is seriously ill, was unaware of the disappearance of his son.
As deputies began searching for the boy, Jakee Contreras was arrested on suspicion of child cruelty, the San Bernardino Sun reported. San Bernardino County Sheriff's Department's records show she is being held at the West Valley Detention Center in Rancho Cucamonga.
The search for Duke was joined Friday by homicide detectives and K-9 units trained to find people.
"Detectives gathered evidence and conducted multiple interviews throughout the day with family members," the news release said. "On Saturday, homicide detectives interviewed Jakee Contreras and, at the conclusion of her interview, she was booked for PC (Penal Code) 187 murder and is being held without bail."
Jennifer Contreras was arrested that same day and booked on a charge of suspicion of being an accessory to murder, the Sun reported. She, too, is being held without bail, but she is at the High Desert Detention Center in Adelanto.
Details of what led to the women’s arrests were not made public.
Those who know the family expressed doubt Friday -- prior to the allegations of murder -- that Jakee Contreras would harm her son.
"That's her, like, pride and joy right there," Duke's godfather, Juan Contreras, told KTLA. "I think he just took off."
"We just need help finding him," another one of Duke's aunts, Leah Contreras, said tearfully. "That's what I ask for. That's the main thing, finding Duke and making sure he's OK."
Investigators continue to look for Duke, who is described as a light-skinned Hispanic boy. He is tall for his age at 3 feet, 10 inches. He has brown hair and brown eyes.
He was last seen in the area of Cherokee Avenue and Pawnee Road in Apple Valley.
Anyone with information regarding Duke's whereabouts is asked to call the Sheriff's Department's Specialized Investigations Division, Detective Narcie Sousa at 909-387-3589 or sheriff's dispatch at 909-387-8313. Callers wishing to remain anonymous can contact authorities at We-Tip at (800)78-CRIME or wetip.com.