Putnam County police found Cash stabbed to death and stuffed into a large wooden box. The man who lived with her, William Austin Johnson, was taken to Vanderbilt University Medical Center with multiple stab wounds.
Johnson, who remains in stable condition Thursday, was able to take his 20-month-old daughter with Cash from the house and drive himself to a White County hospital.
Police later arrested Wayne Gary Masciarella, 27, on Johnson's information. Masciarella was taken into custody in Cookeville and charged with first-degree murder. Investigators believe Cash and Johnson invited Masciarella to their home Tuesday night when a fight broke out and the stabbing occurred.
The first 911 call was placed at 10:40 a.m. Wednesday, but police followed the cell phone's ping location to the wrong address. A second 911 call, 20 minutes later, led them to Cash and Johnson's home, where they discovered Cash's body.
Putnam Count Sheriff David Andrews said it was too early to comment on the murder weapon or a motive, but suggested it may have been drug-related.
Tommy Cash, the brother of the late singer and Courtney's grandfather, issued a statement on behalf of the family Thursday.
"We ask for your prayers for the Cash family at this time. Courtney and her boyfriend are beloved members of my family and like you we have a lot of questions and emotions that we are beginning to sort through today. We ask for you to respect our privacy and appreciate all the support that the public and media has always offered my family, as we handle the loss of my grand-daughter, pray for the father of my great-grand child and journey through the search for justice on this violent act. We are completely heartbroken. It is a time like this that we are grateful for our faith and trusting the loving guidance of God."
Notable deaths of 2014 [PHOTOS]