The Reporter was the major flaw of this movie
As someone posted in another thread:
...the idea that someone in an actual situation would see and do all these stupid things at once in order to build a plot is just ridiculous.
Ah, there's the flaw. The reporter was so unintelligent and downright reckless for someone who is supposed to be an aspiring journalist/documentarian that the movie -- which is supposed to have a "true" feel to it -- suffered.
Ron (the reporter) doesn't do a background check on Walter until AFTER he gallivants with him halfway around the U.S.A.
On their trip to Texas, Walter shoots at him with a rifle while he runs in terror... but he continues to work with him.
Next, he interviews Walter's ex-wife. Her evasive answers about Nov. 22, 1963, made it obvious even to me that Walter wasn't in the hospital for gallstones... but Ron doesn't get a clue, and he continues to work with him.
Next, he accompanies Walter to Bethesda Naval Hospital, where his Marine CO looks terrified to see him and says outright that Walter is crazy... but Ron STILL doesn't get an inkling that Walter Ohlinger could be a mentally unstable time bomb just ticking away, and he continues to work with him.
Then Walter KILLS his CO in the hospital... but Ron continues to work with him.
At the hospital, Walter asks Ron to give him a minute alone with his CO, John Seymour. My immediate thought was, "Oh no. Ron, you must refuse that request." But, to my horror, he obliged. Not only that, but he took the camera with him, which means that any confession Seymour makes to Walter in confidence would not be available for the documentary, which was the whole point of going there.
I thought a reporter was supposed to have a healthy dose of skepticism and was supposed to check his facts. But Ron swallowed Walter's story whole at every turn. He never entertained the thought that threatening phone messages could have been planted by Walter himself or that people in darkened motel parking lots were simply there as guests and not there to follow Walter.
Now I know that maybe it was the director's intent to show that Ron was as delusional as Walter. Ron was unemployed, not even a full-fledged reporter (just a camera man for now), who wanted so much to believe that he had the story of the century that he only saw dollar signs and future acclaim instead of the holes in Walter's account.
Fine. But at least convey that without damaging the realistic tone you're trying to achieve. With smarter writing (which would also have heightened the suspense), Ron would have come to a gradual realization that parts of Walter's story didn't fit; or Ron seeing Walter's more sociopathic side would have been delayed until later in the movie (when it was too late for Ron to extricate himself); or Ron could have confronted Walter with background check results early on, but then Walter would have explained things away and re-convinced him of the magnitude of his story.
As it is, we don't see Ron have any doubts or fears -- just annoyance at Walter's more dangerous exploits. He just lets himself be yanked around by the tail for a psychopathic journey, making him seem like an even bigger patsy than Oswald.