The Meagher County News is the newspaper of record for the county. I'd contact the Meagher County-City Library, 406-547-2250 and ask if they have those newspapers after 16 Aug 1945 on site.
If not, ask them where they are stored.
I think you'd also want a copy of Frank's death certificate. You can order one the Clerk & Recorder, Meagher County, 406-547-3612. Their web iste is http://meaghercounty.mt.gov/clerk_recorder.html
I don't know where coroner reports are filed but contact info for the County Sheriff/Coroner can be found at http://lepc.meaghercounty.net/node/69
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