Feeley in December 2011 said the value of the fraud alleged in the South Canterbury case exceeded "anything in the history of white-collar crime in New Zealand".
Feeley also described the 14-month probe into the company - which began after Beattie left - as the "most resource-intensive and time-consuming in recent history".
But Beattie yesterday said that in his view the investigation was "inept".
"I know for a fact they didn't talk to all the people they should have talked to. When you charge someone with a so-called $1.6 billion fraud you better have done your job properly," said Beattie, who now runs a litigation consultancy business with two other former SFO staff.
Beattie, when discussing the most serious charge laid in the case, said the SFO did not interview key people.
This charge alleged that Sullivan, ex-SCF chief executive Lachie McLeod and former director Robert White were complicit in deceiving the Crown into letting the finance company into the Retail Deposit Guarantee Scheme.
This scheme bailed out a majority of South Canterbury investors to the tune of $1.58 billion after the company's collapse in 2010.
But Justice Paul Heath found the charge was not proven.
Beattie yesterday said documents were missed by the SFO and interviews conducted by the office were not up to scratch. "The interviews were some of the poorest I've seen in terms of trying to get to the bottom of things," he said.
SFO director Julie Read said yesterday she was satisfied there was enough evidence to warrant bringing a case.
"In this case, we have failed to satisfy the court to the required standard in relation to Mr McLeod and Mr White but I consider that the case was investigated thoroughly and that our counsel presented the best possible case to the court."
Asked to respond specifically to Beattie's contentions, Read said: "SFO investigations are carried out in a dynamic environment which is complex and pressured and I am satisfied that, given the context, the interviews, as with the rest of the South Canterbury investigation, were carried out by experienced and capable staff."
Ex-boss may try to recoup costs
At least one of the South Canterbury Finance defendants acquitted of wrongdoing is considering trying to get costs back from the Crown.
Jonathan Eaton, Queen's Counsel for former South Canterbury chief executive Lachie McLeod, said all the defendants had spent "significant resources" answering serious allegations.
"As part of the washup, from our perspective, we'll be having a very close look at our entitlement to seeking some sort of contribution to the costs that have been incurred," Eaton said.
The Herald understands that the total defence costs could come to more than $1 million.
Eaton said he would be inviting other South Canterbury defendants to join the application for costs if it went ahead, including the two men - Terry Hutton and Graeme Brown - whose charges were withdrawn before the trial began.
A court can order thata successful defendant be paid a "just and reasonable" sum towards the cost of a defence.
The judge can have regard to whether the prosecution had sufficient evidence to support a conviction and whether it took proper steps to investigate the matter.
