A Texas mother was found dead inside an SUV with her two young daughters on Thursday morning, less than 24 hours after they were reported missing.

Authorities believed that the woman likely died of an overdose before her children succumbed to heat stroke as they were trapped inside the vehicle.

Police found the bodies of Natalie Chambers, 31, and her daughters Isabel, 4, and Elise, 2, around 10 a.m. inside a blue Ford Escape in a parking lot at Farmers Branch, near Dallas.

According to MSN, they had last been seen alive Wednesday morning, when they left their home in Forney. Chambers was supposed to take her children to a play date in the nearby town of Grapevine, but they never arrived.

Chambers' family immediately filed a missing persons report with Kauffman County Sheriff's Office on Wednesday afternoon after several calls to Chambers' cell phone went unanswered.

Following concerns from family members, police searched an area, where Chambers might have been traveling. The next day, authorities found the SUV in a parking lot near a furniture store along Midway Road and Interstate 635.

Farmers Branch Police Department Officer Steve Rutherford said police, who found Natalie's SUV, observed that there "were three occupants inside the vehicle and the tragic discovery was made that all three occupants of the vehicle were deceased."

In an inForney.com report, it noted that relatives and law enforcement believed that Chambers likely died from an apparent overdose of an undisclosed substance and her two daughters were likely died as as result of heat stroke after being left in the back of the vehicle amid sweltering heat.

The Fox4 News reported that a nearby worker saw the SUV in the parking lot, but he said it didn't appear anything was "unusual."

"To be honest with you, we didn't see anything wrong, or gunshots or anything like that, nothing unusual," Amado Silva said. He noted that windows were rolled up and they didn't notice there was someone inside or see anything suspicious around the car."

Chambers allegedly had a history of drug and alcohol abuse and recent bouts of depression, according to her family and friends. An unnamed family member said Chambers was an amazing mom, but she recently became more depressed because of the ongoing coronavirus pandemic.

Chambers' sister, Jessica Purcell, released a statement to CBS News after the discovery of the bodies.

"We are all devastated that the girls had to witness such a tragedy and suffer themselves," said Purcell. She said she also remembered her sister as a "charismatic" and "hilarious" mother, who loved her daughters.

"I always used to tell her that I am glad she did it first, so I can get parenting tips from her. Elise and Izabel were happy and so very smart and witty," Purcell added.

Surveillance footage obtained by investigators showed that Chambers drove into the parking lot near the furniture store at around 9 a.m. on Wednesday. That afternoon, temperatures soared to 93 degrees.

Authorities said no suspect is being sought at the moment since there were no apparent signs of foul play. They said they still waiting on the Dallas County Medical Examiner's Office to determine the cause of death for the family members.

Police said the county's Medical Examiner is expected to complete official autopsy reports this week.

Check these out:

Florida Man Faces Fraud Charges After Spending COVID-19 Relief Funds to Buy Lamborghini

COVID-19 Survivor Loses Most of His Fingers Due to Complications

Migrant Children in Texas Hotel Will Not Be Expelled, Immigration Officials Say