Within hours of being called in, Sgt. Matthew Ritco seized the note from the Edmonton barracks room where Langridge's body was found, and listed the veteran soldier's last communication as the second item on his crime-scene inventory.
It then disappeared from military records associated with the case and did not resurface until 14 months later, when Langridge's parents, Shaun and Sheila Fynes, were notified of its existence.
"I just seized the items, (as) they were potentially ... evidence," Ritco told the public inquiry that's probing the circumstances of Langridge's death and the Canadian Forces investigation that ensued.
"I wasn't trying to cover anything up, and say: 'OK, I'm going to take the suicide note and keep it off to the side and no one will ever know about it.' It was one of the items I seized."
The Military Police Complaints Commission is examining the family's claim that the investigation into Langridge's death in March 2008 was biased and predisposed towards clearing the name of the Canadian Forces.
In the note, Langridge wrote he could no longer stand the pain, and asked that only a small, private memorial service be held. Instead, a large service, including the military, was held in Edmonton.
At the early stages of the investigation, Ritco hadn't ruled out foul play, he said, defending his decision to conceal the soldier's last wishes because he couldn't be certain that the note was authentic.
"Potentially, he didn't write it," Ritco said under questioning from inquiry lawyer Mark Freiman.
"At the end of the day, it turned out to be a suicide, but if it wasn't a suicide, and I had erred and said: 'OK, I'm just going to give the suicide note up for (the bereavement) of the family,' then I may have potentially gave away evidence."
That answer left Freiman mystified.
"If the only thing you're worried about is whether the note is authentic or not," he asked, "what is the harm of telling anyone and everyone, 'We discovered a note, we don't know with certainty whether it's authentic or not, but this is what it says,' and leave it to the family to decide?"
In hindsight, releasing the note would not have compromised the investigation, Ritco responded. But he quickly added that the military had no policy on suicide notes that would have allowed him that kind of discretion.
"It was a judgment call," he said, acknowledging that the Langridge case was the first case of sudden death he'd investigated.
Ritco was unable to explain why, two months after the death, he didn't disclose the existence of the note in a conversation with the victim's mother. He was equally uncertain about why the note was not listed on an inventory of personal effects that were to be returned to the family.
The military didn't mean to withhold it for 14 months, he said.
"As lead investigator, I have to bear part of the responsibility on that," Ritco testified. "It should have been returned, but it wasn't. It wasn't that we intentionally tried not to return it. It fell through the cracks, and for that I'm sorry."
The question of whether or the not the young soldier had been placed on a suicide watch in the days leading up to his death was examined on Thursday. It is material to the family's allegation that the military was negligent.
Ritco said he was never able to determine conclusively whether a suicide watch had been ordered, but conceded he could have asked more questions of the regimental sergeant major about what kind of "watch" had been placed on the victim.
"Chief Ross said it wasn't a suicide watch. I took it at face value that it wasn't a suicide."
The soldier's body was left hanging for 90 minutes after investigators arrived. The trooper who discovered the body testified earlier he didn't have a knife to cut it down.
Ritco defended his decision to not take any action by saying the coroner was in charge of the scene and didn't tell him to remove Langridge's remains and cover them.
Coroner Dennis Caufield has already told the inquiry that he only needed a few minutes to take a few photos and some notes.
Note to readers: This is a corrected story. An earlier version identified the inquiry lawyer as Rob Fairchild.