Oteri is the father of "Saturday Night Live" alumnus Cheri Oteri and the two men were longtime friends and roommates, The (Nashville) Tennessean reported.
A police spokesman said the two men allegedly had been drinking and got into a fight Saturday night. Fagan allegedly slashed his friend with a pocket knife on the wrist, called another friend to come help and left their home. However, he was intelligible on the phone and no one came to check on Oteri, police said.
Later that night, Fagan was arrested for drunken driving and when he got out of jail Sunday afternoon, he called a friend to check on Oteri. It was that person who found Oteri dead, police said.
Fagan is known for penning a number of country's top songs, including John Michael Montgomery's "Be My Baby Tonight," The Tennessean said.