Among the highlights at this year’s Hot Docs, which wrapped April 27, were true-life crime documentaries that reeked with the smell of death as they probed murder most foul and engaging.

Forget the tabloid docs that fill U.S. cable channels like A&E or Discovery. Hot Doc’s genre-bending documentaries follow in the tradition of Errol Morris’ The Thin Blue Line or Brother’s Keeper by Joe Berlinger and Bruce Sinofsky – films that investigate a murder but don’t try to exploit it.

Consider Susan Gray’s Killer Poet (U.S.), which had its world premiere in Toronto.

The film portrays – from multiple points of view – the life of Norman Porter, a convicted Massachusetts killer who served 25 years in jail before he escaped to Chicago and lived a double life for two decades as a local poet, until his re-arrest in 2005.

The structure of the film comes from the testimony of people who either knew Porter as a cold-blooded killer who evaded justice for 20 years, or as Jacob ‘J.J.’ Jameson, the Chicago poet who performed endless good deeds for his neighbors and local church.

The film employs the approach of the best true-crime docs, which allow those most affected by the crime – a victim’s friends and family, police officers, witnesses and the killers themselves – to talk about their experiences, and then talk some more.

Sometimes too much. Gray said she caught flak from police and court personnel she interviewed who expected a one-sided portrayal of the crimes, as you’d find on Dateline NBC or A&E’s American Justice.

‘They wanted the film to be about a violent criminal that got away and it took 20 years to catch up with him, and this is the story of the hunt,’ she explains.

Of course, as these stories are pulled from the headlines, audiences may very well know the outcome of the murder trial in question ahead of seeing a true-crime film.

They will have little understanding, however, of how the crime itself came about. That storytelling role was taken up by New Zealand filmmaker Annie Goldson in her latest documentary, An Island Calling, which also screened at Hot Docs.

Goodson tells the sensational story of the murder of two gay men in Suva, Fiji in 2001 with deliberate understatement.

‘I did feel a need to go beyond the sensationalism of headlines to get more in-depth,’ the filmmaker says.

In 2001, Fiji Red Cross director-general John Scott and his partner Greg Scrivener were murdered in the name of God by a young aboriginal man.

As she tells the story of the killed and the killer, Goodson reveals a post-colonial Fiji driven by lines of class, blood and history.

Hot Docs also programmed a true-murder doc that unashamedly puts viewers through an emotional wringer – Kurt Kuenne’s Dear Zachary, a California filmmaker’s homage to his best friend, Andrew Bagby, who was murdered in Pennsylvania in 2001 by a jealous ex-girlfriend from Newfoundland.

Kuenne’s doc requires a spoiler tag. The filmmaker said he never intended his film to see festival or theatrical release. He just wanted to create a home movie to honor his childhood buddy.

The filmmaker set himself a tall task in the film’s opening prologue: ‘to travel far and wide, to talk to everyone that ever knew and loved [Bagby]. To learn everything there was to know, and to make one last movie with him. I had no idea how many years it would take or how I would even know when I was done.’

But as Kuenne began to crisscross the U.S. to interview and capture footage of Bagby’s friends, everyone’s grief was compounded by news that his alleged killer, Shirley Turner, was pregnant with his unborn son while fighting extradition back to the U.S. to answer the murder charge.

With that bizarre twist, Kuenne’s film turned into a present for Zachary, a young tot who would never meet his father.

Part of Kuenne’s whip-saw narrative is Bagby’s parents, David and Kate, traveling to Newfoundland to fight for and eventually share custody of Zachary with their son’s apparent killer.

But that legacy was permanently lost when Newfoundland authorities released Turner on bail. While free, Turner killed again – this time drowning herself and Zachary.

So Kuenne’s very personal film, now set for North American theatrical release, has become a call for bail reform, not least from Bagby’s parents, who attended the Hot Docs screening.

‘When Andrew’s parents speak out for reform, they want their story told publicly,’ Kuenne says.

And with that, the role of thoughtful true-crime docs emerges, long after the camera crews and correspondents leave the crime scene, well after a body is buried and friends and family get over the worst of sudden loss and absence.

And that is to bring about social and societal change for the better, which is the best any filmmaker can aspire to.