Samantha Moreno Rodriguez, 35, was booked into a jail in Denver until she could be extradited to Las Vegas, where her son Liam Husted was found dead along a hiking trail on May 28.
Detectives have yet to determine a motive for the homicide.
The boy could not be immediately identified when his body was first discovered and investigators worked tirelessly to piece together the mystery surrounding the child.
Investigators announced they had positively identified him on Monday and simultaneously launched a nationwide search for his mother.
The 7-year-old was last seen leaving San Jose on May 24 with Moreno Rodriguez, Las Vegas Metropolitan Police Lt. Ray Spencer told reporters at a press conference Monday.
Spencer said that investigators were able to link the homicide case to a missing person’s case out of California with the help of the San Jose Police Department.
A family friend had recognized the composite sketches released to the media and alerted San Jose police on Friday that the boy might be Liam Husted. She said she had not seen him or his mother in over two weeks.
Liam’s father also made a report to police on June 1 after not hearing from his son or Moreno Rodriguez. He did not believe his son was in danger at the time and did not want to file charges against Moreno Rodriguez.
Spencer said the father is not a suspect in the case.
The child's grandfather, Chris Husted, told FOX5 Las Vegas that his family was distraught after learning the tragic news.
"It is a complete tragedy and Liam will be very missed," he said. "My son is very distraught by the news. Liam was a special needs child, at a disadvantage and dependent on others' kindness. Unfortunately, his mother took that away."
Investigators learned that the mother and her child were last seen in the San Jose area on May 24 driving a 2007 dark blue Dodge Caliber that Spencer said was packed full of belongings.
They were able to track her movements to Laguna Beach, California, on May 26 and then Victorville, California, later that afternoon.
On the morning of May 28, a group of hikers discovered Liam’s body, which went unidentified for 10 days, on the Mountain Springs Trailhead near Las Vegas.
Moreno Rodriguez’s vehicle was then seen traveling on I-70 near Grand Junction, Colorado, on May 29. Moreno Rodriguez was last seen in the vehicle on May 31, when she arrived at a Denver-area hotel and checked into a room by herself.
Investigators had asked employees of hotels or motels in the Las Vegas valley to check their registries on the days of May 27 and 28 to see if Moreno Rodriguez checked into their establishments.
The Las Vegas homicide section can be reached by email at firstname.lastname@example.org. Anonymous tips can be provided by contacting Crime Stoppers by phone at 702-385-5555 or online at www.crimestoppersofnv.com.