The Washington Post's Michael Birnbaum reports from Nice, France a day after at least 84 people were killed when Mohamed Lahouaiej Bouhlel, 31, drove a truck into a crowd celebrating Bastille Day. (Michael Birnbaum,Jason Aldag/The Washington Post)

Soon after this idyllic city was rocked by a horrific attack, the prime minister speculated that the man responsible was “probably linked to radical Islam one way or another.” Then, the Islamic State called him a “soldier” in an invisible army of terrorists, though it offered no proof to support the claim.

But emerging details suggest that Mohamed Lahouaiej Bouhlel, the man who bulldozed bodies Thursday in a mile-long rampage along Nice’s storied seaside boulevard, lived in much the same way that he died: isolated and alone.

When authorities fatally shot him in the front cabin of the truck he had rented for his heinous mission, they killed a man who never quite appeared to be at home in any of the places, communities and families he had known.

Born in Tunisia in 1985, Bouhlel left his native country sometime between 2009 and 2010. His father said he remembers a deeply troubled son who struggled with what he described as a history of mental illness.

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Speaking from Msaken, about 75 miles south of Tunis, Mohamed Mondher Lahouaiej Bouhlel told French television in comments broadcast Saturday that, as a young man, his son had “psychological problems that caused a nervous breakdown.”

“He would become angry, shout, break everything around him,” Bouhlel said. “We had to take him to the doctor.”

His sister, Rabeb Bouhlel, told the Reuters news agency much the same. “My brother had psychological problems,” she said, “and we have given the police documents showing that he had been seeing psychologists for several years.”

His arrival in France did not appear to have given Bouhlel any peace or stability. Although he found a wife, with whom he is reported to have had three children, he allegedly beat her until she threw him out of their apartment, in a low-income complex on the north side of Nice.

Although she was detained for questioning on Friday, her identity has not been released.

Eventually, Bouhlel developed a criminal record — though, according to Paris prosecutor François Molins, no known connections with terrorist networks or radical groups. Instead, petty crimes were his mainstay: As recently as March, he received a suspended sentence for armed assault.

When he moved into an apartment of his own, the neighborhood he chose was Nice’s Abattoirs area, a working-class district where the city’s former slaughterhouse was located.

Unlike the apartment he had shared with his family, in an active community, his second apartment was on an anonymous thoroughfare in a peeling building next to a string of empty storefronts and parking lots.

Neighbors there said they were largely afraid of Bouhlel. Jasmin Corman, 38, said he had “fixed eyes” that terrified her and her two children, 14 and 7.

“He was always alone,” she said.

Standing in the doorway of her apartment on the building’s ground floor — directly below Bouhlel’s first-floor apartment — she recounted Saturday how he recently stood on the stairwell and silently stared at her as she was locking her door.

When she turned around, Corman said, there he was.

“It’s horrifying to realize you were living beneath a murderer,” she said, adding that she was planning on moving in the near future.

In any case, Corman was watching Bouhlel, too.

Corman, a Muslim who observes Ramadan, said that all throughout the Muslim month of fasting, a ritual that is one of the five pillars of Islam, Bouhlel smoked and drank, occasionally returning to the building smelling of alcohol.

For Muslims, these behaviors are strictly taboo, suggesting that Bouhlel had little connection with the religion.

She also noticed him outside the building with a young blonde on more than one occasion. “It was not his daughter. There were caresses,” she said.

Rebab Bouhlel said her brother rarely called home to Tunisia but recently had begun to do so more often. “Over the past month,” she told Reuters, “he was calling us every day and he sent us money.”

“He called several times a day,” she said.

According to Tunisian media, one of those calls was made the day of the attack. Bouhlel apparently called his brother to tell him about his troubles, mostly his divorce. He also reportedly said he planned to return to Tunisia soon.

If he had been somewhat alienated from his family, Bouhlel was arguably more alienated from the community of his new neighborhood.

One block down the street from his apartment stands the René Arziari Primary School. In an attack in which many of the 84 dead were children, two of them — young boys named in a makeshift memorial as only Loan and Sabry — happened to attend this school.

On Saturday afternoon, the school’s parking lot was empty save for two people: Dalida Renier, 37, and her 9-year-old son, Ethan, who had been in the same class as Loan and Sabry. They were standing in front of the makeshift memorial.

“We are sad,” a tearful Renier said. “But mostly we’re angry that someone would kill children like these.”

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