Police are now searching for the boy’s 11-year-old stepbrother and his father.
According to Lt. Raymond Spencer of the Las Vegas Metro Police Department, the mother contacted police overnight.
Spencer said the mother told police that a sketch of the child was released Friday morning by a hiker, who resembled her son.
According to Spencer, the mother later positively identified the boy after detectives showed him pictures of her body.
According to Spencer, a multi-state amber alert has been issued for stepbrother Eden Montes, who was seen at 9 a.m. Thursday with his 8-year-old brother and his father.
According to the police lieutenant, 37-year-old Jose is not in contact with Montes’ father and is seeking the public’s help in locating Montes and his son.
Spencer said police want people in the Sacramento, California, area as well as southern Utah to be on the lookout for Montes and his son.
He was last seen in a 2015 white GMC truck with a license plate LV U00X. The truck was pulling an RV with a checkerboard pattern on the sides and rear. The truck also has a sticker with the words “Mr. Express” in the lower right corner of the rear window.
“We are doing everything possible to locate 11-year-old Eden and we want to find him alive,” Spencer said.
Police originally sought the public’s help to identify the body found by hikers on Friday morning.
According to Las Vegas police, the boy was found lying in a wooded area at the Mountain Springs Trailhead near mile marker 20 on State Route 160. The area is about 25 miles southwest of the city of Las Vegas.
Police said that shortly after the boy was found at around 7:45 am (10:45 pm ET) on Friday morning, medical personnel declared him dead, police said.
Authorities are not releasing information about injuries on the body, Spencer said. The boy’s cause and manner of death will be released by the Clark County Coroner’s Office.
The police department tweeted, “Investigations by the LVMPD Homicide Section indicate the victim must have been in the area for the past 12 hours.”
CNN’s Ray Sanchez, Danielle Sills and Holly Yan contributed to this report.