Michael Brian Miller stood stoically as he listened to his sister-in-law recount the day he killed his wife and daughter.

Araceli Santoyo described her sister, Adriana Miller, as a loving wife who cared deeply for Michael despite his mental problems. Yet, she said, he viciously betrayed Adriana, murdering her and the couple’s daughter in a fit of rage last May.

“She would have done anything and everything for you,” Santoyo told Miller. “She could never have imagined in her worst nightmares that one day she would have to try to protect herself from you.”

Miller was sentenced to life in prison Thursday for the murders of his wife and 10-year-old daughter. He was given an additional 10- year sentence for attempting to murder his 4-year-old son.

In October, Miller, 29, pleaded guilty to using a kitchen knife to stab his wife and daughter to death. He also admitted attempting to kill his son, but the boy narrowly survived.

The state had sought the death penalty for Miller, but Judge Paul McMurdie of Maricopa County Superior Court withdrew the request at the urging of the victim’s family.

More than two dozen emotional relatives watched Thursday’s proceedings from the courtroom gallery.

Miller’s brother, Mitchell Miller, sobbed as he addressed the court, saying Michael was a good husband and father but suffered from a debilitating mental illness. Miller is reportedly bipolar and schizophrenic.

“I know with all my heart that the man I know did not do this,” Mitchell Miller said.

He described how the family constantly worried about Michael’s condition, wondering whether he was taking his medication and getting enough sleep.

“Every time we thought Mike was getting better, there was another setback,” Mitchell said.

According to a Glendale police, Michael Miller called 911 on May 30 to report he had just murdered his family.

Miller told police he lost control after getting into an argument with his wife about not sleeping enough the night before.

He said “God and Lucifer” told him to kill and that he was “consumed by Satan.” He said he was furious but did not understand why he was so enraged.

Police who responded to the call found Miller’s son was breathing and the boy was rushed to St. Joseph’s Hospital and Medical Center. Miller’s wife and daughter were found motionless on the dining-room floor.