When Knoxville-based mother Lisa Smith heard the phone ring while she was at work, she had no idea that her next conversation would completely change her life. “Heartbreak doesn’t even begin to describe it,” she told Inside Edition.

Earlier that day, Lisa had left her 16-month-old daughter Mia with their in-home daycare provider.

But now the daycare provider was calling with life-shattering news: Mia was not breathing.

The toddler had always been oddly skilled at keeping a beat and her parents hoped she’d one day get into music. Sadly, those dreams were dashed when they learned that the little girl had died.

The official cause of death was positional asphyxia.

Valerie Wackerly, the daycare provider, had reportedly left the toddler in her car seat to nap. Wackerly then left Mia with her husband while she brought her own child for a doctor’s appointment. When they returned, Mia was no longer breathing.

In the 911 call, you hear the woman’s husband tell the operator that one of the babies in his wife’s daycare isn’t breathing and that her face is turning purple. The daycare provider attempts CPR but when asked for an update from the operator, the husband responds:

“She has bubbles coming out of her mouth. Her toes are blue.”

The toddler was rushed to the hospital, where she later passed away. At the time, Lisa and her husband had no idea that Mia had been found in her car seat. Wackerly had visited the family in the hospital but had neglected to mention that the Mia had regularly taken naps in the seat.

According to Sharon Evans, a registered nurse, letting a child sleep in a car seat indoors is extremely dangerous.

These seats are meant to be placed on a solid base. While sleeping, children’s heads can easily fall forward and block off airways, or children can slide down and strangle themselves on the straps. This can cause, what is known as, positional asphyxia – when a person can’t get enough air to breathe due to the position of their body. This is the same cause of death listed in Mia’s case.

Now Mia’s heartbroken parents are warning others of the dangers of letting their children sleep in car seats indoors.

“It was our assumption that Mia napped in a crib and to learn otherwise was very devastating,” Lisa said. “I walk around town and see people using a car seat on the seats at restaurants or putting them on the floor at tables.”

“I literally walk up to people and I say, “You know, I had a daughter who was seventeen-and-a-half months who passed away and I just want you to be really careful.”

Valerie Wackerly ultimately pled guilty to involuntary manslaughter. In addition to leaving Mia in the car seat, she also left the toddler with her husband, who was not certified in childcare. “We knew from day one there was no malicious intent,” Lisa told Inside Edition. “But she made a series of mistakes that cost our daughter her life.”

According to the Des Moines Register, Wackerly was barred from providing childcare for children who are not her own. She was also ordered to record a PSA on the dangers of letting children sleep in car seats indoors. It’s to be played weekly for three years on a Knoxville radio station.

Lisa and her husband are currently raising two boys, but they will never forget the stain that Mia’s death has left on their souls.

She would have turned 6 in December of last year.

“Heartbreak doesn’t even begin to describe it, to know that this was so preventable. This should never happen to any family.”

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Sources: Inside Edition, Des Moines Register, 10News WBIR,