Howell County authorities now believe they know who is responsible for killing a man whose body was found last weekend in a garage after a fire.

Two brothers -- Jonnathan D. Graven, 31, and Jared D. "Skip" Graven, 23, both of West Plains -- have been charged with first-degree murder in the death of Ricky J. Johnson, 22, of Pottersville, Howell County Sheriff Robbie Crites said.

The brothers also have been charged with felony counts of arson, abandonment of a corpse and tampering with a motor vehicle, the sheriff said.

Both are in the Howell County Jail on $1 million bond.

Johnson's body was discovered Saturday when firefighters responded to a fire in a garage.

Investigators on Tuesday served a search warrant on a Howell County residence and collected evidence relating to Johnson's death.

Although no one was home, investigators discovered what appeared to be new linoleum on the floor and fresh paint on some of the walls, the Howell County Sheriff's Department said. Several items were found and seized as evidence.

The next day, four people located in a Thayer motel room were taken into custody for questioning, but two of the individuals were later released. Several items were seized following a search of the motel room and two vehicles.

Sheriff Crites expressed his condolences to Johnson's family and said the sheriff's department -- along with several other agencies -- have been working around the clock since Johnson's body was discovered.

"I'm not sure the public realizes the effort and time that goes into these types of cases, and I'm thankful to these other agencies and investigators for their help," he said.

The Missouri Fire Marshal's Office, the Missouri Highway Patrol Division of Drug and Crime Control, the Missouri Highway Patrol Crime Lab, the South-Central Drug Task Force, the West Plains/Howell County SWAT Team, West Plains Police Department, Thayer Police Department, Oregon County Sheriff's Department and the Missouri Department of Conservation assisted the Howell County Sheriff's Department in the investigation.