Authorities say Mark Anthony Conditt, the man suspected in the recent series of deadly Austin-area bombings, died in a blast that he intentionally triggered as police closed in on him Wednesday.

Questions now turn to Conditt's background and what drove his killing spree.

A friend of the suspect, Jeremiah Jensen, describes Conditt as shy, smart and thoughtful. Jensen attended church and says he was "pretty good friends" with Conditt in 2012 and 2013. Jensen says Conditt never exhibited tendencies that made him think he'd be "capable of something like this."

Austin, Texas had been on edge for nearly a month after a series of five bombings — which authorities believed were connected — killed two and injured several others.

"When I met Mark, he was pretty rough around the edges, came off as dominant, pugnacious in nature," Jensen told NPR member station KERA, where he was once an intern. But after getting to know him, Jensen says, "he started to soften, I really started to see him bloom. ... I always thought he was going to bloom into a productive person."

Jensen chalked Conditt's shyness up to homeschooling — they were part of the same homeschool community and Jensen says many "homeschool kids" he knew struggled to make friends and socialize with people outside their immediate families.

"He was a deep thinker, very smart guy. I just think a lot of people didn't understand him," Jensen, who last saw Conditt around four years ago, says.

"Four or five years ago, this was not Mark. Mark was funny and happy for the most part. ... He was an intense person and could be hard to love but he was a person. He was alive."

Jensen remembers thinking to himself that Conditt had "a lot deeper personality than a lot of people would give him credit for, would stick around to find out."

Hearing the news of Conditt's actions and death now, he says, feels "surreal."

"You never go around in your life thinking, like, this person that I knew, that I ate with, that I talked with is someday going to kill people, and kill himself," Jensen.

Jensen hasn't had contact with Conditt in recent years, and says he doesn't know what would have driven him toward a violent path.

"I think that maybe he was lonely when he died. I think that he might have isolated himself," he says, "I don't know why he succumbed to hatred, or the loneliness or the sadness but I suspect that that was what was going on."

Jensen says he wishes Conditt would have reached out to him to share his struggles and that he could have "just talked to him one time before he went down this path."

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