Angela Phakhin had been convicted in June of the first-degree murder of Maiya and the sentence was pronounced last Friday, the district attorney's office in Sacramento said.

Phakhin's fiance, Untwan Smith, has also been charged in the case and is awaiting trial.

The pair moved to California in February 2016 from Arkansas and were living in their car, authorities said.

Over a two-week period in June 2017, the couple subjected Maiya to extreme summer temperatures, they added.

On one occasion, she was left in a car for four-and-a-half hours and the next day for nine-and-a-half hours, which resulted in her death, prosecutors said.

"Phakhin had been warned repeatedly to protect Maiya and was advised to take her to a cooling shelter, but she did not accept the offers," prosecutors said. "After Maiya's death, Phakhin told law enforcement that she and Smith were trying to remove the lustful demons from Maiya."

Phakhin and Smith were arrested on June 28, 2017 in Rancho Cordova, north of San Francisco, after their SUV was spotted by police parked the wrong way.

Officers began searching the car after a records check revealed that Smith had an outstanding warrant in Arkansas.

Maiya was found underneath blankets in the back seat and was pronounced dead at the scene.