There is no evidence to implicate former crime intelligence boss Richard Mdluli and three others in the death of Oupa Ramogibe, the Boksburg Magistrate's Court found on Friday.
"The death was brought by an act prima facie amounting to an offence on the part of unknown persons," said Magistrate Jurg Viviers.
"There is no evidence on a balance of probabilities implicating Richard Mdluli, Samuel Dlomo, Colonel Nkosana Sebastian Ximba, or Lt-Col Mtunzi-Omhle Mthembeni Mtunzi in the death of the deceased."
Ramogibe died in February 1999 after marrying Mdluli's mistress Tsidi Buthelezi.
The Ramogibe family had accused Mdluli of killing Oupa, but Mdluli has claimed there is a plot to implicate him and that the Ramogibe family was working with police.
Viviers said the inquest was about who killed Ramogibe.
He said other allegations, such as kidnapping, assault, and intimidation, were irrelevant to the inquest.
Mdluli was accused of the murder, along with Dlomo, Ximba, and Mtunzi, but the charge was provisionally withdrawn in February pending the outcome of the inquest.
Also withdrawn were charges of intimidation, kidnapping, assault with intent to do grievous bodily harm, attempted murder, and conspiracy to commit murder.