"This has been a horrific murder spree," said Johnson County Sheriff Dwayne Price.
Officials with Kentucky State Police told WKYT they got the call of the shooting around 3:40 p.m. Saturday, CBS News reported.
According to WKYT, the Johnson County Sheriff's Office said they found two people dead in the kitchen of a home. The suspect was not at the scene, but deputies later received a tip about his vehicle.
Deputies said two additional victims and the suspect were found dead inside an apartment. Police said gunman apparently took his own life after committing the murders.
"The lives of four innocent victims were taken," Price said. "The perpetrator then took his own life. There are no words to describe the heartbreak in seeing four lives taken due to the actions of one man. I have worked in law enforcement for 34 years. This is one of the most disturbing acts of violence I have ever seen."