OTTAWA -- The pain and suffering endured by the family of an Edmonton soldier who killed himself should be used as a springboard for systemic changes to the treatment of veterans and their loved ones, the family's lawyer said Wednesday.

The investigations into the 2008 suicide of Cpl. Stuart Langridge were handled in an inept and inexperienced manner, retired colonel Michel Drapeau told the Military Police Complaints Commission hearing.

"It has created an extra layer of pain and turmoil that was preventable and correctable, had a modicum of transparency, accountability and basic compassion been displayed from senior military leaders," Drapeau said.

After eight months of work and 92 witnesses, the hearing ended Wednesday, with Drapeau and lawyers for the government pressing their case for a final time.

The public interest hearing was convened following complaints from Langridge's family that the investigation into their son's death was biased and designed to absolve the military.

Langridge, a veteran of Afghanistan and Bosnia, hanged himself in March 2008 after being ordered back to base following treatment for drug and alcohol addiction in a civilian hospital.

His family contends the military treated him as a malcontent, and that helped drive him over the edge.

Langridge's reasons for taking his own life aren't for the hearing to decide, said Drapeau. What matters, he argued, is how the investigation was carried out.

"Each of the three (National Investigation Service) investigations were conducted in an unsubstantiated manner," Drapeau said.

"Taken together, these investigations aptly demonstrate the NIS lacks experience, expertise, structure and independence to conduct these types of investigations."

Lawyers for the federal government asserted otherwise, noting the 13 military police officers who are the subject of the complaint by Langridge's family have between five and 23 years of experience each.

"This commission cannot ignore the practical and legal limits that police officers operate under when they exercise their powers," said lawyer Korinda McLaine.

McLaine said the government believes the commission's focus should be narrow in scope: whether the steps taken and conclusions reached by the 13 MPs fell within the range of reasonable outcomes, given the policies available to them at the time.

"You must not hold the subjects to a standard of perfection or ask if, given what we now know, the same decisions would have been made," she said.

The inquiry heard how military police concealed Langridge's suicide note from his parents for 14 months, claiming the sheet of paper was evidence in a suspicious-death probe. The investigators stuck to the line even though the coroner at the scene described it as a clear-cut case of suicide.

Had the note been released immediately, several subsequent complications -- including difficulties figuring out who was Langridge's next of kin and what kind of funeral he wanted -- could have been avoided, the hearing was told.

But the NIS has acknowledged it mishandled the note and has improved its procedures since, McLaine said.

"Although it may be tempting to look back on the investigations with the perfect lens of hindsight, that would not be fair to the subjects in this complaint," she said.

There were also conflicting claims about whether the troubled soldier was on a suicide watch prior to his death. If so, the military would have been liable for his death.

The inquiry also heard how the final military police report into the death was heavily rewritten and censored.

Sgt. Matthew Ritco, the lead investigator, testified that direction came down from "higher" to create two case summary files, one written by him and another rewritten version to be delivered to the chain of command, including Langridge's commanding officer.

The final draft removed all but one reference to the victim having been on suicide watch before his death.

All of this was to protect the military, not respect Langridge or his family, Drapeau said.

"The army, and its commanders, are considered and treated as a brand that needs protecting," he said.

"This means that, if there is wrongdoing by the chain of command, and it becomes public knowledge, there is an entire team of CF public affairs officers committed to ensuring that the outcomes are projected in a way that best protects the brand. Unfortunately, that is exactly what happened here."

Commission chair Glenn Stannard was urged to not examine the case through a political lens, despite the attention the case has drawn since 2008.

"You must not be swayed by the political debate and rhetoric, you must not be influenced by the publicity surrounding this issue and you must be cautious and rigorous in your examination of the veracity of the allegations," McLaine said.

A report from the commission will take months to complete; an interim version is first submitted to political and military leadership before a final version is released publicly.

Langridge's parents said the close of the hearing was a milestone moment.

"We put Stuart's most personal parts of his life on display -- and this family, too," said his mother, Sheila Fynes.

"And I hope it wasn't for nothing. Some positive change has to happen here. We'll see."