He was moved to the New Prison’s hospital where he was kept for “observation”.
Acting area commissioner for the Department of Correctional Services Vusumuzi Ndlovu confirmed Soni’s stay in the prison hospital, adding that he had since returned to his cell, awaiting his sentencing at the end of October.
But sources said Soni was “in and out” of the hospital, unable to stay a full night in his cell.
A source close to Soni, who asked not to be named, said Soni was afraid of being in prison and his health had taken “a serious knock”.
Soni was convicted in the Pietermaritzburg High Court last month of the murder of Dr Bhavish Sewram .
Sewram was shot by hitmen while he sat in his bakkie outside his Chota Motala Road surgery in May 2013.
During the trial, it was revealed that it was a “crime of passion” after Soni discovered Sewram was having an affair with his wife.
The court previously heard that Soni suffered from hypertension and heart disease and was on medication for depression.
Soni is expected to be sentenced on October 26.