The parents of a Canadian soldier who committed suicide hope to finally get the answers they have been seeking for four years, with the start of a public hearing Tuesday into their son's death.

Cpl. Stuart Langridge hanged himself on March 2008 in the barracks at CFB Edmonton where he was stationed.

The 29-year-old had served on tours in Bosnia and Afghanistan and was suffering from post-traumatic stress disorder when he died.

He had also been struggling with alcohol and substance abuse since his return from a six-month tour in Afghanistan in 2005, and his family later learned he had attempted suicide on six previous occasions.

Why that information was kept from them, and why it wasn't until months after his death that the military handed over the suicide note Langridge had left, are some of the questions Shaun and Sheila Fynes hope to have answered at the Public Interest Hearing being held at the Military Police Complaints Commission in Ottawa.

"Our son was in the military, he became ill, he was cared for by the military community and he died as a result of his service, we honestly believe," Sheila told CTV's Canada AM on Tuesday.

"And I think there are some steps along the way that could have been done differently but hopefully the commission is going to do a really good job here, we're really hopeful."

Though the Canadian Forces National Investigations Service carried out an earlier probe into his death, his parents believe the aim was to exonerate the military of any responsibility, rather than uncover what went wrong.

They hope that will be different this time around.

"We've just tried desperately to find the truth and we're very relieved and very pleased that the Military Police Complaints Commission listened and acted on our complaint," Shaun said. "We look forward to clearing our son's name and hopefully helping other soldiers so they don't end up in the same position."

Shortly before Langridge succeeded in killing himself, he checked himself into a psychiatric facility at a local hospital in Alberta.

His parents said he was responding well to treatment and asked to stay in the facility until he could be transferred to a facility in Ontario, but the request was denied.

He was discharged, and killed himself within two weeks.

That prompted the Fynes to hold a parliamentary news conference last fall, which was quickly followed by an apology from Chief of Defence Staff Gen. Walt Natynczyk.

The family fought for and eventually received the Memorial Cross and Sacrifice Medal for their son. He was also included in the Seventh Book of Remembrance.

In addition to learning more about how their son's illness and death was handled, the couple hopes their efforts will result in better treatment for other soldiers facing similar challenges.

"Hopefully along the way, even if we save the life of one soldier then this will all have been worth it and Stuart will not have died in vain," Sheila said.

The hearing is expected to last 10 to 12 weeks, and Sheila plans to attend every day. The Fynes will be represented by retired Col. Michel Drapeau.