Story highlights Courtney Cash, grandniece of Johnny Cash, was found dead in her home

Police say she was apparently stabbed by a friend, who is in custody

He was charged with first-degree murder

Cash's boyfriend was also hurt in the stabbing and remains hospitalized

Courtney Cash, the grandniece of musician Johnny Cash, was found dead in a box in her home in Tennessee, and a friend is charged in her death, according to Putnam County sheriff's officials.

Wayne Gary Masciarella, who is in custody, is charged with first-degree murder, and more charges are expected, Sheriff David Andrews told CNN.

Masciarella apparently had gone out Tuesday night with Cash and her boyfriend, William Austin Johnson. The couple lived together, and when all three returned to the apartment early Wednesday, there was an altercation. Cash and Johnson were both stabbed, officials say.

Johnson managed to get away from the apartment and gave a statement to investigators at a local hospital.

Based on his statement, the sheriff said authorities arrested Masciarella within a couple of hours.

Johnson remains hospitalized at Vanderbilt University Medical Center in Nashville.

Cash's grandfather, Tommy Cash, who is Johnny Cash's brother, said on Facebook: "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. "