This story was updated April 8, 2018, at 11:59 p.m. with more information.
UPDATE: East Ridge police have identified the second homicide victim as 22-year-old Avery Gaines of Ringgold, Ga.
UPDATE: Authorities with Jasper County (Miss.) Sheriff's Office have confirmed on Facebook that Casey Lawhorn's vehicle was found on Interstate 59 near the Vossburg exit in Jasper County.
Lawhorn was not in the vehicle but is presumed to still be in Jasper County. He is armed and still considered very dangerous.
If seen, authorities are asking the public to not approach him but to call police immediately.
UPDATE: East Ridge assistant police chief confirmed that the Mississippi Highway Patrol has located Casey Lawhorn's vehicle.
Allen said they report the vehicle is occupied, but they have not approached yet.
They are calling a SWAT team in and will notify East Ridge police once they know if Lawhorn is deceased or still alive.
UPDATE: A person purporting to be the shooter in this morning's double homicide in East Ridge posted details of the incident on Facebook in a post that now appears to have been removed.
East Ridge police say some time before 5:30 a.m., Casey Lawhorn shot and killed his mother, Vi Lawhorn, and one of his friends who was spending the night.
"Before I start, I need to emphasize that I take full responsibility for my actions," Casey Lawhorn wrote. "Nothing anyone has or hasn't done to me caused this, my decisions and my failures are my own."
He then detailed the events as they unfolded that night. He said he picked up his mother from a bar at 12:30 a.m. When they got home, he shot and killed his friend as he slept on the living room floor with a stolen .22 long rifle. He shot and killed his mother by 1:30 a.m.
Lawhorn said he wrote the post from the side of Interstate 59 in Mississippi after his vehicle broke down. The East Ridge police are aware and are working to alert the relevant agencies in that region and gain further verifiable information.
East Ridge police Assistant Chief Stan Allen said they are not yet able to confirm whether Lawhorn's narrative is accurate.
ORIGINAL STORY: Neighbors gathered in their driveway in East Ridge, Tenn., today after police say a man shot and killed his mother and another person just hours earlier in the house next door in the 1700 block of John Ross Road.
Casey Lawhorn, 23, shot his mother, Vi Lawhorn, and a friend of his in the head some time before 5:30 a.m., according to East Ridge Police. The friend's name had not been released before press time Sunday evening, as family had not yet been notified.
"He gave me the creeps," Terry Kilgore said of Casey Lawhorn. Kilgore lives next to the small white house where the two people had been shot. The family had just moved in some time in February, he said.
A rocking chair sat on the front porch Sunday afternoon, and pink and white flowers grew in a small flower bed to the side, just in front of the driveway.
Vi Lawhorn was "a sweetheart, nice, cordial," Kilgore said. But the son "wasn't too friendly" and never talked even when Kilgore tried to say hello numerous times.
Christopher Heyer lives a house over and agreed with Kilgore. He also said Casey Lawhorn seemed very introverted.
Kilgore said he talked to Vi Lawhorn several times in their yards with "over the fence gossip," and both he and Heyer said they'd often see her outdoors planting flowers.
"It's a shame," Heyer said. "It surprised everyone."
Neither of the men heard any of the gunshots.
Casey Lawhorn called police and told them what had happened, according to a news release, but he fled the scene before police arrived. He was believed to have been in Dade County at the time, driving a gold 2002 Ford Taurus with a Tennessee tag number W0327L.
Dade County Sheriff's Office posted to Facebook confirming that a vehicle matching that description had been seen at a gas station in Dade County at approximately 5:30 a.m., but there is no evidence to suggest Casey Lawhorn stayed in the area after he fueled up.
Casey Lawhorn is not in Cloudland Canyon, according to the sheriff's office.
East Ridge police believe Lawhorn is continuing further Southwest through Georgia.
Casey Lawhorn is a white male, 5'5" and weighing 108 pounds. Anyone who sees him or the vehicle should call police immediately. He is considered to be armed and dangerous.