Inset: Jasmaine Smoak (Wilkes County Sheriff's Office). Background: News footage of the apartment in Atlanta, Georgia, where Colby Cooks was found dead (WAGA).

A Georgia woman who was responsible for watching her friend's children has been charged with murdering of one of them.

Jasmaine Smoak, 32, was charged with murder, aggravated assault and cruelty to children in connection with the death of 4-year-old Colby Cooks. According to a press release from the Atlanta Police Department, Colby was found dead inside an apartment in Atlanta, Georgia, on Monday evening, when officers were performing a welfare check. Police announced on Thursday that a second woman, 30-year-old Jasmine Jenkins, has also been arrested in connection with Colby's death. She was charged with murder and cruelty to children.

After police tracked Smoak's vehicle to another county, they saw she was with three other children, including Colby's brother, 5-year-old Cayden Cooks. Cayden was suffering from "visible injuries" that required him to be hospitalized.

Local Fox affiliate WAGA spoke to Destyne Akoon, a friend of the boys' mother, who said Cayden's father was at his son's bedside while he recovered from severe head trauma and other injuries. Akoon told WAGA that the boys' mother was incarcerated and entrusted Smoak with her children while she was behind bars. But she said "since they were in the care of Jasmaine," the boys allegedly had "marks" on them.

WAGA reported that the Fulton County Medical Examiner's Office conducted an autopsy on Colby and determined that he died of blunt force trauma. His manner of death was listed as homicide.

Police said Smoak fled the apartment with the surviving children before officers arrived to perform the welfare check. She was tracked to Wilkes County using license plate readers. At the time of her arrest, she was initially charged with cruelty to children and concealing a death.

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Authorities have not identified the relationship between Smoak and the other two children she was found with.

Smoak was booked into the Wilkes County Jail and is expected to be transferred to Fulton County. Her name did not appear on the inmate roster as of Thursday. Authorities did not release her next court date.