Rocky Mountain National Park is visited by millions of people every year; in fact, it's the fourth most-visited national park in the country. And yet, exactly nine years ago on September 29, 2012, it was where Toni and Harold Henthorn went together to celebrate their anniversary — and there were no witnesses when Toni died that day.

Now, a Hulu docuseries called Wild Crime: Murder in the Rocky Mountains is investigating the events that unfolded that day.

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Suspicion surrounding Harold Henthorn arose largely due to the fact that his first wife, Lynn, also died tragically, under very strange circumstances. Lynn Henthorn was reportedly crushed by their Jeep in a freak accident in 1995 — in remote Sedalia, Colorado. An episode of CBS' 48 Hours revealed that authorities believed Henthorn's two wives did not just tragically die coincidentally, but that he killed both of them because he was after their life insurance proceeds, reportedly 'worth millions.'

Now, ABC News' first-ever Hulu exclusive Wild Crime is honing in on Toni Henthorn's 'fall' from Deer Mountain in Rocky Mountain National Park in 2012, and what really happened that day.

'Wild Crime tells the story of one of the most notorious murders ever committed in a National Park,' Hulu says. 'The series follows Special Agent Beth Shott of the Investigative Services Branch as she and her team doggedly pursue the suspect through three years of twists and turns until he is arrested and convicted.'

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