No audio was allowed in department three of the Tulare County Courthouse on Monday, as various witnesses testified in the case against Bernardo Renova.
Renova, 19, is accused of killing Mary Doris Steif during a botched burglary near Tulare last April.
Related: Elderly victim of prowler burglary died of a heart attack, Tulare County Sheriff's Office says
That night, Renova was reportedly casing other houses, prompting at least one 911 call, before he entered Steif's trailer. Deputies arrived to the area quickly, and arrested Renova outside the trailer.
Inside, Tulare County Sheriff's Detective Brandon VanCuren says Steif was dead, surrounded by miscellaneous items, including a lamp, a phone, and a fly swatter -- signs that a struggle had occurred.
Dr. Gary Walter performed Steif's autopsy, and determined she died of a heart attack.
Walter, who said that Steif suffered from heart disease, testified that her death could have been caused by feelings of stress or fear. He said she also had bruises to her lip, upper arm, and knee.
Steif lived by herself, and according to her niece, had zest. At 83-years-old, she drove a pickup truck, did her own laundry, and went to church twice a week.
For her death, Renova not only faces a murder charge, but a special allegation of killing her while trying to burglarize her home.
He faces a maximum punishment of life in prison without parole or the death penalty.