Police in South Africa have arrested a murder suspect who while trying to cover up a killing started a fire that ended up taking at least 77 lives in Johannesburg last year.

The 29-year-old man, who wasn't named, said he had killed a man in the basement of the rundown building on the night of the fire by beating him and strangling him, according to South African media reports of the testimony. He said he then poured gasoline on the man's body and set it alight with a match.

The shocking confession came when the man was testifying at the public inquiry into the causes of the nighttime fire in Johannesburg in August, one of South Africa's worst disasters.

He testified that he was a drug user and was told to kill the man by a Tanzanian drug dealer who lived in the building.

The inquiry he was testifying at isn't a criminal proceeding and his confession came as a complete surprise. The inquiry is looking into what caused the fire and what safety failures might have resulted in so many people dying, and he testified because he was a resident of the building.

The panel in charge of the inquiry ordered that he not be identified after his testimony and a lawyer leading the questioning of witnesses said that his confession couldn't be used against him because it wasn't a criminal hearing.

Hours later, police said they had arrested the man after his testimony. "A suspect was arrested in connection to the Marshalltown fire," police spokeswoman Dimakatso Nevhuhulwi said Wednesday.

The suspect is expected to appear in court "soon" on charges of arson, 76 counts of murder and 120 counts of attempted murder, police said.

Illegal occupation of disused buildings in the city center is widespread, with many said to be under the control of criminal syndicates who collect rent from occupants.