A bicyclist found McCormack's body July 29 on a steep hillside alongside Highway 59 between Noel and Lanagan.
Authorities are almost certain the body was McCormack's and are awaiting results of DNA and dental records tests.
McCormack, 25, Noel, was originally from Carthage.
A cause of death has yet to be determined.
McCormack's children, four-year-old Siah Casillas, 20-month-old Saidah Noor, and seven-month-old Intisar Mahamed, the subjects of an Amber Alert after McCormack's body was discovered were found Thursday at the Des Moines, Iowa, home of one of their father's relatives.
Des Moines Police Department spokesman said Paul Parizek said the relative had been caring for the children for a few days.
"He didn't give (her) much of an explanation. He said, 'You have guardianship of these kids now' and he left."
After the father did not return for several days, Parizek said, the relative became suspicious and contacted the police.
A Justice for Jessica Go Fund Me page has been established with the following message:
Late July Jessica body was found in Noel,Mo.... a mother of 3 beautiful girls #JusticeforJessica will help lay her to rest ... and provide anything necessary for the girl in this time Jessica was hungry for the Lord and now she walks with Jesus !!!! Gone to soon ... let’s come together and give her the resting place she deserves !
The accompanying video is from We Are Iowa Local 5 News.