OTTAWA - The RCMP watchdog says the Mounties should not investigate their own members in the most serious cases - especially when someone has died - due to conflict of interest.

In a new report, the Commission for Public Complaints Against the RCMP recommends sexual assault and serious injury cases involving Mounties sometimes be turned over to outside investigators to ensure independence.

The commission, which spent 19 months studying the controversial issue of the RCMP investigating itself, calls for several policy and legislative changes to avoid actual or perceived conflicts. Currently, the national police force has discretion to decide how such investigations will unfold.

"Overall, it is the CPC's contention that criminal investigations into members should not be treated the same way as any other criminal investigation," says the commission's report released Tuesday.

"As the seriousness of the offence alleged against a member rises, the discretion for the RCMP to respond as it deems appropriate must be removed and mandatory requirements should be inserted in its place."

Several recent incidents have highlighted the thorny subject of police investigating police, including the case of Robert Dziekanski, who died at the Vancouver Airport in 2007 after being hit with an RCMP Taser, and that of Ian Bush, shot and killed by a Mountie in B.C. four years ago.

In November 2007, complaints commission chairman Paul Kennedy began looking into the practice of the RCMP investigating itself in cases involving serious injury or death.

He examined 28 cases from a five-year period, including six deaths.

"We sought to answer the following question: Can the current process of the RCMP investigating itself legitimately engender confidence in the transparency and integrity of the criminal investigation and its outcome?

"Based on the results of our research and analysis, the informed commission answer is that it cannot."

He told reporters the force does not track investigations against its own and has no understanding of the scope of the problem.

"There is currently no national, centralized co-ordination of member investigations," he said. "That means that no member of the RCMP, including the RCMP commissioner, can tell you how many criminal investigations have been undertaken into its own members.

"More serious is that no one can tell you how many members have been investigated for serious injury, sexual assault or death nor can they identify how many charges have been laid against their members nor what the outcome was."

Kennedy's research found the RCMP investigators were "free of bias" and approached their assignments in a professional and conscientious manner.

However, he identified several "inappropriate" patterns in the case files:

-One-quarter of primary investigators personally knew the member under scrutiny;

-In 60 per cent of cases, a single investigator was assigned, placing the investigation at risk for potential conflict of interest or perception of bias;

-In almost one-third of cases, the primary investigator was of the same or lower rank as the subject member, creating potential for intimidation.

In general, Kennedy found nothing in policy or legislation to guide the appropriate handling of a member investigation.

The report calls for national standardization of policy on criminal investigations involving RCMP members so they are conducted in the same way across Canada.

Kennedy urges legislative changes that would give the complaints commission authority to refer an RCMP member investigation to another criminal investigative body. This would automatically happen in cases involving death.

In cases involving serious injury and sexual assault, the complaints commission and a new national registrar for member investigations would decide whether to refer the case to another police service or hand the investigation to a mobile RCMP critical incident team.

In less serious criminal matters, the new national registrar would have discretion to decide the best option.

The registrar would also manage, track, train and advise on all issues related to member investigations.

The RCMP greeted the recommendations coolly last month in a reply to Kennedy's interim report.

RCMP Commissioner William Elliott said in a letter the report's language was "unduly negative" and that a complete overhaul and expansion of the investigative model "may not be warranted."

Elliott said, however, that a forthcoming RCMP policy on member investigations would address a number of Kennedy's concerns.

"Those concerns and your recommendations will be considered as we finalize our policy."