The Jasper County Sheriff's Office said that suspect Casey James Lawhorn was found dead in Vossburg, Mississippi, from an apparent self-inflicted gunshot wound.
The two victims are Lawhorn's mother, Vi Lawhorn, and a friend.
Police said Casey Lawhorn typed a 1,000-word Facebook post about how early Sunday morning, he apparently was fed up with his mother and his friend and decided to kill them in his East Ridge, Tennessee, home.
East Ridge Police confirmed to WTVC that Mississippi Highway Patrol located Casey Lawhorn's vehicle in Jasper County, Mississippi, around 7 p.m. Sunday.
Casey Lawhorn was not in the car, police said.
This comes after Casey's brother told WTVC that he had learned Casey was traveling southbound on I-59 through Mississippi.
East Ridge Police Assistant Police Chief Stan Allen told ABC News that the Facebook post appeared to be authentic, saying Lawhorn "posted a pretty specific message on Facebook detailing the crime."
According to the Facebook post from Sunday evening, Casey Lawhorn, admitted to picking up a "stolen .22 LR rifle" from his bedroom and about 1:30 a.m., walked up to his friend dozing on the living room floor and "shot him in the head once." The Facebook post said the young man "seemed to die instantly."
Then, the post suggests, he marched to his mother's dark bedroom while she was sleeping. The post claimed that his mom was inebriated when he tried pulling the trigger.
But the gun jammed, according to the post, which stated that he left the room momentarily to fix the weapon, and then returned. That's when he "rapidly got off two shots" in the dark.
"She started screaming the worst scream I've ever heard," according to the post. "Movies really don't do justice to how true terror sounds."
The gun jammed again, according to the post, and after fixing it a second time, Lawhorn then allegedly turned a light on and "shot at her twice more and it was over."
The post stated that Lawhorn later swiped heroin and cash from his dead friend's pockets and wallet but spared his mother's dog, Oscar.
Afterward, the post claims that Lawhorn was struggling with college and that he was hoping to commit suicide.
"Surely any normal person would wish death on themselves after doing what I did, seeing what I saw, and hearing what I heard," according to the post.
The name of the friend has not yet been released as the next of kin has not been notified.
Allen told ABC News that dispatchers received a call from Mississippi, about 40 miles from Casey Lawhorn's home, from a man they believe to be Lawhorn tipping them off on the homicides.
"The suspect called us and identified himself and talked to our dispatchers for some time," Allen said. "He told them that he had committed the crime and that he was going to a location north of our city to find a secluded spot to kill himself."
Officers arrived at the home and found Lawhorn's mother and a young man dead from apparent gunshot wounds.
ABC News contributed to this report.