Mississippi investigators believe they found the body of a man who was on the lam after penning a blood-curdling Facebook post detailing how he killed his mother and best friend.

The Jasper County Sheriff’s Department announced on Facebook on Monday that it discovered a body in the Vossburg, Mississippi, area that authorities believe is 23-year-old Casey James Lawhorn.

In the Facebook post, Lawhorn describes grabbing a stolen rifle from his bedroom and shooting 22-year-old Gaines “in the head once” as he dozed on the living room couch.

His friend “seemed to die instantly,” he wrote.

He then marched to his mother’s bedroom, where she was “disoriented from alcohol” after a night of drinking.

Lawson tried pulling the trigger, but the gun jammed. He went out to fix the weapon and then “rapidly got off two shots,” but missed because the room was dark.

“She started screaming the worst scream I’ve ever heard,” he wrote. “Movies really don’t do justice to how true terror sounds.”

“She shouted, ‘You shot me! You’ve killed me! Why?’” he recalled.

After shooting his mother again, Lawhorn swiped heroin and cash from his friend’s pockets — but spared Oscar, his mom’s dog.

“I didn’t hurt our dog or cat, in case anyone was wondering about the animals,” he wrote.

Lawhorn wrote that he was struggling since starting at Middle Tennessee State University and that he’d been suicidal since high school.

“Surely any normal person would wish death on themselves after doing what I did, seeing what I saw and hearing what I heard,” he wrote. “All that’s waiting on me is life in prison, or maybe the death penalty.”

“I’ve spent a lot of time thinking about murder, wondering what it feels like. But I’ve barely felt anything,” he concluded.

On Sunday evening, dispatchers received a phone call from Mississippi — 40 miles from Lawhorn’s home — tipping them off about the killings.

“The suspect called us and identified himself,” East Ridge Assistant Police Chief Stan Allen told ABC News. “He told us 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.”

Authorities later discovered Lawhorn’s abandoned 2002 gold Ford Taurus in Jasper County, Miss., and suspect he may be headed to Georgia.