Story highlights The mother smoked marijuana after closing her kids in the car, authorities say

She originally told police they locked themselves inside, the sheriff's office says

(CNN) A Texas mother whose two children died of heat exposure after she left them in a car was arrested Friday, local authorities said.

The Parker County Sheriff's Office arrested Cynthia Marie Randolph, 24, for the deaths last month of her 2-year-old daughter and 16-month-old son after she left them in the car to teach her daughter a lesson, the sheriff's office said in a news release.

"Throughout multiple interviews, Randolph created several variations of the events which led to the death of her children," the release said.

But the investigation, which also involved the Texas Rangers, revealed a different story.

On May 26, the news release said, Randolph found the children playing in the car around 12:15 p.m. When she told her daughter to get out of the car, she refused, and Randolph closed the car door "to teach her daughter a 'lesson,' thinking 'she could get herself and her brother out of car when ready,'" the release said.

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