Colonel Tembinkosi Kinana said on Friday Martins (55) was due to appear in court for perlemoen racketeering when he was attacked by three men before 9am.
When police arrived at the scene, Martins was lying on the road with a bullet wound to the head.
Kinana said police were investigating the motive for the shooting and no arrests had yet been made.
The National Prosecuting Authority said Martins's case had been on the roll to arrange a date for heads of arguments to be submitted.
Martins and four others were arrested during an operation in December 2004 and January 2005.
The controversial pastor, renown for burying gangsters, and two others had apparently tried to exchange drugs for perlemoen. – Sapa