(CNN) At least three of the seven people killed in Sumner County, Tennessee, were related to the suspect in the slayings, including his mother, father and uncle, Tennessee Bureau of Investigation Director David Rausch said Monday.
The victims also included three generations of another family, a 12-year-old girl among them, and a woman who is not related to Cummins, Rausch told reporters. The victims were likely dead for more than a day upon being discovered, he said.
Michael Cummins, the 25-year-old suspect who has a long criminal record and authorities say was released from prison earlier this year, is hospitalized after being shot by a sheriff's deputy. His injuries are not life-threatening. He has not been formally charged.
An eighth victim, also Cummins' relative, is in the hospital in critical condition, Rausch said.
Authorities discovered six of the bodies and the injured victim off a rural road between Westmoreland and Fairfield, small towns about 50 miles northeast of Nashville. A seventh body was found at a home less than a mile from the primary crime scene, police said.
The victims were identified as follows:
Tennessee investigators said the home where six of the victims were found dead over the weekend was one of the most complex and gruesome crime scenes they'd ever encountered.
"This is one of the most horrific cases that I've ever had to encounter and deal with," said District Attorney Ray Whitley, who has been in his position since 1980.
Added Sheriff Sonny Weatherford, who has been in law enforcement since 1983, "I've never seen anything that would even come close to this."
A family member called police Saturday after finding four of the bodies, and the TBI quickly announced investigators had found a fifth body at a nearby home.
The next day, the bureau said it had found two more bodies at the first house. Investigators declined to say how the victims were killed, citing the ongoing investigation.
After Cummins was identified as the suspect, police said, a search plane located him in a creek bed about a mile from the first home. More than a dozen SWAT team officers converged on the creek, the TBI said.
"The situation escalated, for reasons under investigation, and resulted in at least one officer firing his service weapon, striking Cummins," the TBI said, adding that no officers were hurt.
Cummins has a lengthy criminal history. According to a TBI background check, it includes pleading guilty to violating a protective order in 2013, entering into a plea deal for attempted assault and a probation violation in 2013, pleading guilty to theft and evading arrest in 2017, pleading guilty to domestic assault and a probation violation in 2017 and convictions in 2018 on aggravated assault and aggravated arson charges.
He was most recently released from prison January 19, Whitley said. Before his latest arrest, Cummins was scheduled to remain on probation until 2027, the Tennessee Department of Correction said.