"I'm thinking, 'wow, this is pretty wild,'" he told CBS News correspondent Steve Hartman.
The only question was: who's lifetime?
"I saw the Western Union telegram and pulled it out and looked at it and knew immediately what it was," Kaiser said.
One telegram began: "We deeply regret to confirm…" And it told the story of a soldier who died - 40 years ago.
Also in the bag were letters and pictures from Vietnam, from that same soldier, a 19-year-old Marine private named Kenny Phares. But there was no way to track down exactly who treasured these things so much they saved them all those years in a bank bag.
So, Kaiser took the pictures to the local news in Portland, Ore.
And sure enough, one woman recognized him … recognized him all too well.
"It just doesn't seem right, me going overseas," one of the letters read. "I'm going to do my best. I love you always."
Kenny's mom Bertha is now 85.
"I'm so thankful we found them," she said.
No one knows exactly how the bag ended up on the street. Bertha says her husband was very sentimental and used to carry those letters and pictures everywhere. But he died nearly 20 years ago. She just assumed the bag was somewhere in the house. She never looked for it and really had no idea it was even missing.
Here's a good question: How can she be so glad to have something back that you didn't know was missing?
"You want me to tell you something?" Bertha said. "I re-read all those letters I re-read that telegram three or four times and yes, I needed that. I needed that very much."
Bertha said her son was buried in a closed casket. She never saw his body.
So for all these years, she now admits, there was a part of her that thought he might still come home.
She never accepted he was dead?
"No," she said. "But I'm going to step over that wall from now on."
Last week Bertha thanked her church for helping her grieve for good.
"It's been a hard time, but I think this is a closing," she said. "I've got so many people that I know love me."
Everybody left with a goodbye hug, including the boy she'd been holding onto for 40 years.
She held the bank bag close to her chest and said, he'll "always be with me."