On the day her two children were found dead, Cynthia Marie Randolph recounted for investigators a mother’s nightmare: She had been folding laundry and watching television while her young daughter and son, ages 2 and 16 months, played in an enclosed sun room on the back porch.

Randolph, 24, went to check on her children after about a half-hour – but they were “gone,” she told police. She said that after a half-hour of searching, she finally spotted their bodies, unresponsive, inside her 2010 Honda Crosstour parked in her driveway.

It was May 26, a day when the high temperature outside Randolph’s home in Weatherford, Texas, reached 96 degrees, according to police records.

Medics pronounced both children dead at the scene, authorities said.

According to the Parker County Sheriff’s Office, when asked how long the children might have been exposed to the high temperatures inside the car, Randolph responded immediately: “No more than an hour.”

Less than a month after the tragedy, Randolph has been arrested after her original explanation for her children’s deaths unraveled. Through multiple interviews with investigators over the past month, Randolph “created several variations of the events” of May 26, police said.