It's every parent's worst nightmare.
A week ago yesterday, Courtney Mazur and her fiancé woke up in their Tomah, Wisc. home at 4:45 a.m. Courtney was helping her husband-to-be get ready for work, and went outside to start his truck.
There, she saw a horrifying sight -- her 2-year-old daughter, Raelyn, "laying face down on my patio with her eyes glazed open like porcelain doll," as she puts it.
"We have motion sensor lights outside, and when I opened the door ever so slightly, the light turned on and I found my daughter," Courtney tells Fox 9.
Raelyn's body was cold and lifeless. She was transferred from a hospital in Tomah to the Mayor Clinic Hospital in Rochester, where she was pronounced brain dead.
Courtney says Raelyn and her 5-year-old step sister apparently decided to go outside to play sometime between 10:30 p.m. and 4:45 a.m. that fateful morning. At some point, Melody decided to come back inside and attempted to bring Raelyn with her, but the toddler decided to stay outside.
She never made it back in.
"I don't think she knows how to open, to push the button to get in the screen," Courtney says.
The 5-year-old told police she and her sister woke in the middle of the night and thought it would be fun to play in the snow. When Raelyn refused to come in, her sister left the main door unlocked, but not the screen door, and it was the latter Raelyn apparently couldn't open.
Courtney takes some comfort in the fact Raelyn's organs have been donated. Her kidneys went to a 47-year-old woman, her liver to a 66-year-old woman.
But Courtney says above all, she hopes her tragic story will encourage other parents to install door alarms, as she's done since Raelyn's death.
"It's just heartbreaking to think if I had done this sooner, my baby would still be here," she says.
If you'd like to help Courtney and her family pay their medical bills, click here.