Supt. Bob Williams will testify Wednesday at the public inquiry into the case. He penned a 28-page document for the RCMP in 2002 in response to a civil lawsuit from the families of two of Pickton's victims.
The Vancouver Police Department has shown some contrition in recent years, admitting the force made mistakes and offering several public apologies, including at the ongoing public inquiry.
But the RCMP has neither apologized nor admitted to any mistakes, instead insisting questions of what went wrong are for the inquiry to answer.
Williams, then an inspector working in Edmonton, interviewed key figures inside the RCMP's investigation of Pickton in Port Coquitlam, the suburban community east of Vancouver where the serial killer's notorious farm was located.
Williams wrote investigators were "dedicated and diligent" and cautioned "we should not be critical of the strides that investigators took" to determine whether Pickton was a viable suspect.
"We (Williams and his review team) are of the opinion the RCMP acted appropriately and followed-up investigative leads with respect to Robert William Pickton," says the report, tabled as an exhibit at the inquiry last fall.
"There is little doubt that the RCMP attempted to exhaust all investigative avenues relative to the suspect. ... Based on our experience and from the interviews conducted, it is suffice to say that nothing would have changed dramatically if those involved had to do it over again."
Specifically, Williams concluded:
— The RCMP considered Pickton its top suspect in the missing women investigation and shared that opinion with the Vancouver police and other departments.
— There was "excellent" co-operation between the RCMP and the Vancouver police department.
— Any delays in the Pickton investigation were the result of several other high-profile cases that were competing for the Coquitlam detachment's limited resources.
— The RCMP was the driving force in the creation of a joint missing women task force with the Vancouver police, named Project Evenhanded.
— Pickton was not the only suspect.
Williams' relative rosy assessment stands at odds with earlier testimony at the inquiry, specifically from Deputy Chief Doug LePard of the Vancouver police, who authored his own internal review that was publicly released in 2010.
Vancouver police and the RCMP each headed up separate but related investigations — Vancouver into the disappearances of sex workers, and RCMP into information implicating Pickton, who had already been accused of trying to kill a sex worker there in 1997.
LePard's extensive report was critical of both forces, but the document saved its harshest criticism for the RCMP.
The Vancouver officer said RCMP investigators were too quick to discount information from several informants who claimed Pickton was murdering prostitutes and disposing of their bodies at his pig farm. All those claims turned out to be horrifyingly accurate.
LePard wrote that the Mounties resisted information from informants even though their allegations were similar to the 1997 attempted murder case. Prosecutors stayed charges against Pickton then.
DNA from two other missing women was on clothing seized from Pickton during that investigation, which sat for years in an evidence locker and was never re-examined by the RCMP until after Pickton's arrest.
The RCMP allowed the Pickton file to remain idle for months in 1999 even as Pickton rose to the top of the suspect list, wrote LePard.
LePard testified at the inquiry that the RCMP was slow to embrace the idea of a joint investigation, which he said was actually spearheaded by a Vancouver police officer.
And LePard was especially critical of an interrogation in 2001 in which two inexperienced officers interviewed Pickton without first consulting with Vancouver police.
In the interview LePard characterized as poorly planned and sloppy, Pickton consented to a search of his farm, but the RCMP never took him up on the offer.
In the end, the RCMP and Vancouver police department's separate investigations into missing women and Pickton failed to crack the case.
Pickton was essentially caught by accident when a junior RCMP officer with less than two years on the force followed up on a tip about illegal firearms and obtained a search warrant.
That officer brought members from the missing women investigation along, where they immediately stumbled upon the butchered remains and discarded belongings of missing women, setting off a massive search of the farm.
Pickton was eventually convicted of six counts of second degree murder and sentenced to life in prison with no parole for at least 25 years.
The remains or DNA of 33 women were found on his farm, and he claimed to have killed 49.
Note to readers: This is a corrected story. A previous version misspelled the deputy chief's name.