June 13 (UPI) -- Mary Duggar, the grandmother of Counting On stars Jill and Jessa Duggar and their 17 siblings, died of an accidental drowning.
Washington County Coroner Roger W. Morris confirmed Duggar's cause of death Wednesday to People magazine after Duggar died Sunday at age 78.
Morris told USA Today Duggar died at her home in Springdale, Ark.
"It appears she slipped and fell into the pool," he said.
The Duggar family had announced Duggar's death in a Facebook post Sunday.
"We are so sad to share that Grandma Duggar (Mary) passed away Sunday afternoon, June 9th, 2019," the family wrote. "She is greatly loved and will be missed so very much!"
Jill, 28, confirmed Duggar's death in an Instagram post Sunday.
"My heart breaks. My grandma died suddenly today! She was an amazing woman of God and such a great example to so many! Grandma, you are greatly missed by all who knew you!" she wrote.
Duggar, the mother of Jill and Jessa's father, Jim Bob Duggar, appeared with her family on the TLC series 19 Kids & Counting and Counting On. The shows follow Jim Bob, his wife, Michelle Duggar, and their 19 children.