Michael Sharp believed in the power of persuasion. The 34-year-old Kansan with the round face and a penchant for plaid shirts would walk, unarmed, deep into rebel-held territory in the Democratic Republic of Congo, sit in the shade of banana trees with rebels and exchange stories.

Inevitably, those stories would turn to the past. "Rebels love talking about the past," Michael once told me.

Michael's deep understanding of how these rebels saw their country's past — the mythical version of that past that they used to justify their own violence — allowed him to emerge from the jungle each time unscathed. And it enabled him, and his Congolese colleagues, to connect with rebels in a way few others managed to do. After every trip, the team of church workers would be followed, days later, by rebels who had been persuaded to surrender and give up the fight. By his count, Michael's team persuaded at least 1,600 rebels to abandon the jungle and come home.

Michael entered rebel-held territory for the last time two weeks ago. He was no longer working for the church group, which had lost its funding. He had been appointed to the U.N. Security Council Group of Experts and was investigating a relatively new rebellion in the Kasai-Central province of the Democratic Republic of Congo. He did what he's always done — headed into the jungle, this time with his interpreter, his Swedish colleague, Zaida Catalan, and their motorbike drivers.

The bodies of Michael and Zaida were discovered in a shallow grave on Monday. The Congolese nationals who were with them are still missing.

I had the opportunity to meet Michael in January 2015. I was struck not only by his optimism and kindness but by his determination — increasingly rare today -- to engage in dialogue with violent people who perceive the world so differently from how he did. Michael's particular calling was in the Democratic Republic of Congo, persuading rebels to surrender, but he believed his approach could be applied to other violent groups, from ISIS to neo-Nazis, that rely on myths to recruit members and sustain themselves.

Michael and I met by accident, both passengers on a commuter boat crossing Lake Kivu, the two-fingered lake dividing DRC from Rwanda. The ferry boat had been chartered by the U.S. State Department for a VIP entourage that included former Senator Russ Feingold, then special envoy to the Great Lakes Region of Africa.

I was there to follow Feingold's mission for a few days. Michael Sharp had talked his way onto the boat to try to save his Peace and Reconciliation program, part of the Congolese Protestant Council of Churches, the program that sent people into the forest to persuade rebels to come home. Their shoestring budget — $12,000 a month — once provided by the government of Norway, had just been pulled. (Sharp was told that the money was diverted to help Syrian refugees.)

Michael was far happier to sit with me, in the stern of the boat, answering my many questions about how he persuades rebels to give up the fight than he was in walking over to the former senator to make a plea for funding.

In our conversation, Michael explained how he approached the very violent rebels. It starts, he said, with understanding their world view of the past as "the good old days and we need to go back to that. And that is the classic narrative of exile." The rebels, he said, were nostalgic for a mythical home and aimed to rewind history to a time that never really existed in the first place. For the Congolese rebels, their fantasy was an era when they — in their imagination — ruled neighboring Rwanda and killed their ethnic enemies with impunity.

How do you find common ground with that?

Michael did not condone the violent ethnic fantasy but acknowledged its existence and understood the psychology behind it. One who dreams so deeply of home, isn't he deeply homesick? That homesickness became a weakness that Michael and his church colleagues aimed to exploit.

Later I sought out some of Michael's Congolese colleagues to understand this better. As I reported on this blog in 2015, one of Michael's colleagues, Emmanuel Kambale, explained the blunt message that he'd deliver to older rebels:

"You," he tells them, "you're over 50 years old, it's too late for you to take over Rwanda. But your children are growing up uneducated in the bush. Don't you see that your children, who are the future of Rwanda, when they go back they'll be the slaves of those who are there! Because they are illiterate!"

That use of the word "slave" is deliberate. For those who dream of ethnic domination, there could be no greater terror.

I spoke to Michael a few times after that ferry ride, but we never met again, despite our plans to. My last image of him will always be back on that boat, watching him talk to Russ Feingold, having finally mustered the courage to approach the former senator. Feingold looks interested, as he often does; Michael is smiling and talks with his hands. I can't hear what he's saying over the boat's motor but I know he's attempting to raise money for the church workers to allow them to continue their risky forays into the bush. That funding never came.

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