A South African court has acquitted Wouter Basson, former head of an Apartheid-era weapons programme, of 46 counts of murder, fraud and drug charges.
During his trial, Basson alleged that Peter Regli, the former head of Switzerland's secret service, was involved in the covert weapons programme. Regli, who was later cleared by a Swiss parliamentary inquiry, denounced Basson's allegations as "slander".
Pretoria High Court Judge Willie Hartzenberg said the prosecution had failed during the 30-month-trial to prove that Basson had committed any crimes. The government plans to appeal the verdict, a spokesman said.
Dubbed "Dr Death" by the South African media, Basson, a cardiologist, declined to comment on the verdict.
Basson headed the Apartheid-era regime's covert chemical and biological weapons programme.
He had faced charges including conspiring to kill two Apartheid opponents in London and supplying muscle relaxants used to kill more than 200 Namibian prisoners, whose bodies were then dropped into the ocean from a plane.
Switzerland's House of Representatives has rejected calls to set up an independent inquiry into the alleged links between the two co0untries' secret services.
However, last November the government announced that a parliamentary committee would reopen investigations. The committee said it still intended to question Basson.
The South African authorities have allowed Swiss investigators to examine documents in a probe of suspected criminal deals, including illegal goods deliveries and spying.
The Swiss defence ministry is also conducting its own probe into alleged close contact between Regli and Basson. In addition, it is also investigating accusations that Regli illegally destroyed documents.
In an interview with swissinfo last August, Regli said the Swiss secret service "had nothing to do" with their South African counterparts during the period in question.
by Samantha Tonkin