"She wasn't even supposed to be there," Hensley said. "She felt bad and wanted to help out."
At 3:15 a.m., shots were fired at the apartment. Jerden, 27, was killed. Fiske was wounded and went for help, Hensley said.
Christensen was hiding behind a locked door in the bathroom when she was found and killed, her mother said.
Police arrested Jerden's roommate, 31-year-old Paul C. Ashton, and another man, 29-year-old Brandon Perry Smith. Ashton is being held on suspicion of two counts of aggravated murder and one count of attempted aggravated murder. Smith was booked on one count each of aggravated murder and aggravated assault.
They are each being held on $1 million bond.
Fiske was treated and released from Dixie Valley Regional Medical Center.
Police on Sunday released few details about what led to the killings.
"We don't believe it was a drug deal gone bad," said St. George police Sgt. Craig Harding, but "we've not ruled out drugs being involved."
Ashton has a pending felony drug possession case, according to court records. A search of Utah court records did not show a criminal history for Smith.
Christensen was only friends with Fiske, Hensley said, and found herself in the "wrong place at the wrong time."
"She knew that a woman needed to move out and she went to help because it was the right thing to do," she said.
Christensen leaves behind her mother, stepfather and older sister.