The lead investigator probing into the plane crash that killed former South African captain Hansie Cronje said it was too early to speculate on the reason behind the disgraced cricketer's death since the authorities are yet to come out with the final report.

Dr Andre de Kock of the Civil Aviation Authority, probing the case, rubbished the claims by British magazine 'The  Observer Sports Monthly' that Cronje could have been murdered since some "feared he would one day tell the full truth, and then many more would be implicated."

"A large part of the accident report had been compiled, and once all the information was received, the CAA would start finalising the report," said Andre, adding he could need another three months to collect details to make an assessment of what could have caused the accident.

"It is a complex investigation. We've already worked through the flight recorder and cockpit recorder - commonly known as the black boxes - as well as documentation relating to the pilots, such as licensing and medicals."

He said the last instrumentation component of the Hawker Siddeley 748 twin-engined turboprop aircraft, needed to help conclude the investigation, would be sent to the United States later on Monday for testing.

The CAA is also putting together the "last pieces of the puzzle" around the aircrash near George that killed Cronje and two pilots last year, Andre said.