The woman had claimed the girls collapsed after smelling flowers at a nearby lake, police said

A Texas mother whose two young children died in a hot car while she partied inside a shed was sentenced to 40 years in prison Wednesday.

Police say that June 7, 2017, Amanda Hawkins, then 19, drove her 1- and 2-year-old daughters to the hospital. The girls were in dire condition and their mother claimed they'd collapsed after smelling flowers at a nearby lake, Kerr County Sheriff Rusty Hierholzer told The Washington Post last year.

But police quickly determined that flowers weren't the culprit. Instead, the girls' mother intentionally left them in her car overnight while she partied with friends, according to Hill Country Breaking News.

The children - Brynn Hawkins, 1, and Addyson Overgard-Eddy, 2 - were trapped in the car for 15 to 18 hours as temperatures in Hill Country reached close to 90 degrees. That evening, someone heard the girls crying in the car and asked Hawkins to bring them inside. "She said: 'No, it's fine. They'll cry themselves to sleep,' " Hierholzer said.

Prosecutors said that Hawkins woke up around noon the next day and had sex before going out and finding the girls, Hill Country Breaking News reported.

"She knew those kids were back there. She left them in that car," Hierholzer said.

Hawkins pleaded guilty in September to two felony counts of abandoning or endangering a child causing imminent danger or death, bodily injury or physical or mental impairment, and two counts of injury to a child, according to People. In a statement, police said Hawkins was initially reluctant to drive the children to the hospital because "she did not want to get in trouble."

Prosecutors said that Hawkins Googled how to revive someone from heat exhaustion while running cold water on the girls in a futile attempt to save them, the Hill Country Breaking News reported.

Her attorney did not immediately respond to a phone call and email requesting comment.

"Those precious little girls would still be here today if this had not happened," Judge Keith Williams told Hawkins during the trial. "People in our community take better care of their pets than you took care of your kids."

Williams imposed four sentences of 20 years each, with two sets running concurrently, bringing her total sentence to 40 years.

A second case in these deaths involves then-16-year-old Kevin Franke, who was also at the party.

Franke entered the car to sleep because there was not enough room inside the shed, according to his attorney. Upon leaving the car, prosecutors say, Franke turned off the engine and rolled up the windows, subjecting the children to the intense heat.

His attorney, Richard Ellison, claims he knocked on Hawkins's door to wake her up the next morning, but she apparently did not answer. When asked whether Franke knew that there were children in the car with him, Ellison replied: "That's unclear, and I'm still trying to sort that all out."

Ellison said it's unclear from the evidence whether the engine was on or off before Franke slept in the car.

"He hardly knew Amanda and was in the wrong place at the wrong time," Ellison said.

Franke was charged as an adult in July with two counts of felony murder in the deaths of the children.

When Brynn and Addyson were taken to the hospital, physician John Gebhart stayed up for more than 40 hours trying to save their lives, he later testified.

Hawkins was giggling and texting at times while defending her flower-sniffing story to doctors, Gebhart testified, according to the Hill Country Breaking News.

"She kept saying, 'This is what happened,' over and over," Gebhart said. He added that the two girls died slowly and probably painfully. Judge Williams reprimanded Hawkins for lying and casting blame on others.

Hawkins made a statement before her sentencing, stating, "I will accept whatever the punishment may be," and that "there are no excuses for what I did."

She added, "I do love them and care about them."

Deaths of children in hot vehicles have fluctuated in recent years. On average, 38 children die in such cases each year, according to kidsandcars.org, although these tragic cases are oftentimes unintentional, as Hierholzer said last year.

"This is by far the most horrific case of child endangerment that I have seen in the 37 years that I have been in law enforcement," Hierholzer said.