PHOENIX -- Phoenix father Jeffrey Duchane pleaded guilty to the murder of his 12-year-old daughter and to the beating of her 9-year-old sister.

“I've been praying for this day," said Virginia Gray, the girls’ grandmother. “I was like, 'How could you do that to your daughters? Your babies?'"

“I’m glad he pleaded guilty. I'm glad he finally realized he let something horrible happen to his daughter," said Kenisha Gray, the girls’ mother.

Investigators said Duchane's wife Reiko Troupe beat Trenay Duchane, 12, and forced her into a scalding-hot bathtub because she didn't do her homework. Police reported finding her younger sister hiding in the shower with burns, bruises and a broken arm.

Duchane not only failed to protect his girls -- records show he admitted waiting days to call 911, even though he knew his eldest daughter was dead.

"I miss her a lot. I miss her so much. When she passed away, a piece of my heart was gone," said Kenisha Gray.

"He was their father. It makes it worse because he was their father and he should have protected them," said Virginia Gray.

Duchane is set to be sentenced in July.

Troupe is already serving a life sentence.