Something struck Tamerlan Tsarnaev's aunt when her nephew arrived in southern Russia last year.
He prayed regularly, she said. He avoided looking women in the eye. His transformation into a devout Muslim was a radical change.
Less than a year since Pateimat Suleimanova last saw her nephew, he is dead. The FBI says he and his younger brother were behind the Boston Marathon bombings that killed three people and injured more than 170. Authorities say Tsarnaev died after a gunfight with police early Friday.
But the suspects' possible motive remains a mystery. And a key question has emerged as investigators comb through clues: What did Tsarnaev do during a trip to Russia from January to July of last year?
According to family accounts, Tsarnaev visited Makhachkala, where his father lives.
After Tsarnaev returned to the United States in mid-July, a video of an Islamic militant known as Abu Dujana was posted and then removed from Tsarnaev's YouTube channel.
Five months after Tsarnaev left Makhachkala, Russian security forces there killed Abu Dujana during a gunbattle that left a home in shambles.
It's unclear whether Tsarnaev ever met Abu Dujana, or had any ties with the militant group he led.
Information about Tsarnaev's trip to Russia has been hard to come by. But speaking to CNN from Makhachkala on Monday, Suleimanova revealed new details about what Tsarnaev did there, and how his family perceived his behavior.
Side trip to Chechnya
Suleimanova said Tsarnaev traveled to Chechnya twice, likely going to see his father's family in Gudermes and Chiriyurt -- towns less than 200 kilometers (about 125 miles) away that were flashpoints in fighting between Russian forces and Chechan rebels during their longstanding tensions in 1990s.
Tsarnaev was born in 1986 in Kyrgyzstan to an ethnically Chechen family, his uncle said last week.
His birthplace is in a part of the world that's no stranger to violence or terrorism, and the Tsarnaev family saw that firsthand.
The family fled violence in Kyrgyzstan and lived in Chechnya when war broke out there between separatists and Russian forces in 1999, Suleimanova told CNN.
But she described her nephew's visit to the region last year as a peaceful trip focused on rebuilding family connections.
"He tried to reestablish family ties. ... He went to see people, people came to see him, and of course, he went to pray," she said.
During the trip, she said, what surprised her and others in the family was the way Tsarnaev's behavior had changed since he went to the United States in 2003. It had become more conservative.
"They hadn't prayed before they went to America. Nobody taught him," Suleimanova said. "He learned everything himself."
The change was notable, she said.
"At the same time," she said, "we were happy about it, because he didn't start doing drugs or alcohol and adopted the path to Islam."
Tsarnaev's parents weren't as devout, she said.
"And it is very strange to me that it was him who adopted Islam, not his father, not his mother, but himself," she said. "But it's not so strange because nowadays the children study Islam and teach their parents, and that's exactly how it turned out with him."
Tsarnaev's behavior made his beliefs clear, she said.
"You know, he and other men don't even touch other women, I mean, he doesn't speak to them (other women)," she recalls. "He could speak to his sisters, his cousins and me, and other women are of no significance to him because it's a sin to even look at other women in the eye."
That faith, Suleimanova said, was one reason she believes there is no way her nephews could be behind the Boston bombings.