The seven people killed in two homes in rural Tennessee included the parents of the suspect and other relatives, authorities said Monday.

Law enforcement officials arrested 25-year-old Michael Cummins on Saturday about a mile (1.6 kilometers) away from one of the Sumner County crime scenes. Tennessee Bureau of Investigation Director David Rausch called the scenes "horrific" and "gruesome."

Cummins has a criminal history, including a conviction for a 2017 aggravated arson arrest. He also has court-documented mental health issues, including an agreement to undergo mental health treatment after he pleaded guilty to 2017 charges of misdemeanor theft and evading arrest.

Cummins was released from jail in the middle of January, said Ray Whitley, the local district attorney general.

Cummins has not been charged in the deaths at this point. Whitley, the prosecutor, assured that his office "will see that justice is done."

TBI identified those killed as 51-year-old David Carl Cummins and 44-year-old Clara Jane Cummins, the suspect's parents; 45-year-old Charles Edward Hosale, his uncle; Rachel Dawn McGlothlin-Pee, the 43-year-old whose relationship to him isn't clear; Rachel's 12-year-old daughter, Sapphire McGlothlin-Pee; and Rachel's mother, 64-year-old Marsha Elizabeth Nuckols. Another victim, 69-year-old Shirley B. Fehrle, was found in a separate home and has no known relationship to Cummins.

An eighth victim, another relative, remained hospitalized in critical condition. Authorities believe the incidents occurred over more than one day, Rausch said.

"This is one of the most horrific cases I've ever had to encounter and deal with," said Whitley, who has been district attorney general in Sumner County since 1980.

Authorities have said officers responding to a 911 call from a family member led to the original discovery of four bodies and an injured person at the first home. The injured victim was transported to the hospital with unspecified injuries. On Sunday, the TBI said in a statement the body of two more victims had been found at the home.

Another body was found Saturday at another home in the area. The TBI believes the two scenes are related. The slayings were near the town of Westmoreland.

Authorities have not said what kind of weapon was used.

On Saturday, TBI spokesman Josh DeVine said at least one officer fired at Cummins after he emerged from the woods. Cummins is believed to have produced multiple weapons and the situation escalated. He remains hospitalized for treatment of what's believed to be injuries that aren't life-threatening, DeVine said.

None of the responding officers were hurt.

DeVine said a state law enforcement airplane helped authorities spot Cummins on the ground in a creek bed.