Three sisters were killed in an accident on Tuesday, after they were smothered by a truckload of canola seeds on their family farm near Alberta, Canada.

The siblings, 13-year-old Catie Bott, and her twin sisters, Dara and Jana, 11, died when the seeds led them to suffocate, but sources give to different accounts of what led to the tragedy. A deputy chief said that the girls fell into the canola seeds as the truck was being unloaded, according to CBC News. But, another telling had the girls were playing on the truck while it was being filled with seeds and were buried, the Edmonton Journal reported.

Regardless of what led to their suffocation, family members and neighbors pulled the girls out and attempted CPR, but failed.

Catie and one of the twins were pronounced dead at the scene, while the other twin was flown to Edmonton's Stollery Children's Hospital in critical condition, where she was pronounced dead at 3 a.m. on Wednesday, according to The Calgary Sun.

The girls' grieving parents, Roger and Bonita Bott, released a statement saying they didn't regret raising their children on the farm.

"Our kids died living life on the farm," the parents said. "It is a family farm. We do not regret raising and involving our kids: Catie, 13, Dara, 11, Jana, 11, on our farm. It was our life."

The sisters are survived by their brother, Caleb, who thanked the community for supporting his family during their time of need.

Investigators are working with the medical examiner's office to determine what exactly happened.