NORTH DARTMOUTH, Mass. — If Dzhokhar Tsarnaev is responsible for setting off pressure-cooker bombs at the Boston Marathon, as authorities allege, he displayed a remarkable poker face at his college campus in southeastern Massachusetts.
The 19-year-old sophomore studied engineering, played soccer and became known for party-hopping and smoking marijuana. When he talked to his friends, it was usually about one subject — girls. As a freshman, he decorated his dorm room wall with two posters: one of Einstein, the other of 12 bikini-clad women on a beach.
"He would talk about which ones had the nicest butt," said Mary Pariseau, a friend who lived on the same floor.
On a Twitter account that Pariseau confirmed as Tsarnaev's, he sounds more frat boy than fundamentalist. He quoted Eminem lyrics, cracked jokes and proclaimed his love for peanut butter, Marshmallow Fluff and Nutella.
"Not being able to find the remote to the tv is probably one of the most reoccurring struggles of life," one tweet said.
Now classmates at the University of Massachusetts Dartmouth are trying to reconcile their good-looking, fun-loving friend with the serious-looking man in the backward white ball cap and gray hoodie in a surveillance video image branded by the FBI as suspect No. 2. Investigators are essentially doing the same.
He wasn't a loner. He wasn't known for angry outbursts. And although authorities say his older brother and alleged accomplice took a turn toward radical Islam in recent years, Tsarnaev showed little sign of religious fervor.
This week, authorities charged him with using a weapon of mass destruction to kill three people, including an 8-year-old boy, and injure more than 200 others. After the bombings, university officials said, he returned to campus for much of the week; students have said they spotted him at the gym and at a party.
On this campus of about 9,000 students, where Tsarnaev has been a student since 2011, there's a sense of shock, even denial, among those who knew him. His friend Pariseau, 20, has found herself asking fellow students to take down vitriolic online comments.
"A lot of us are very confused on campus since we were such good friends with him and all of the sudden he's mixed up in these horrible things," she said. "I don't believe it even though the facts are right in front of me.
"He was just normal. That's why it's so unbelievable that it happened and why a lot of us at UMass think he didn't want to do it but was influenced by his brother or his uncle or whoever. It's so not him."
Beginning Thursday night, investigators allege, Tsarnaev and his brother, Tamerlan, 26, shot to death an MIT police officer and engaged in a fierce battle with law enforcement officers in a nearby community that left Tamerlan dead. Police cornered Tsarnaev hours later in a suburban backyard as he hid in a boat. He remains hospitalized.
Later, in his room at the university's Pine Dale Hall, police found what they described as "a large pyrotechnic," BB's and a black jacket and white hat similar to what suspect No. 2 wore.
An ethnic Chechen born in Kyrgyzstan, Tsarnaev came to the U.S. about a decade ago. His family settled in Cambridge, Mass., where he was captain of the high school wrestling team and competed in the 126-pound class. He rarely spoke of his heritage, said former teammate Sanjaya Lanichhane, 22, and always asked to be dropped off a block from his home when friends gave him rides.
"I know he's a bad guy," he said, "but for me, he's still a good guy."
Tsarnaev was awarded a $2,500 scholarship by the city to attend college. It's unclear why he chose the university in Dartmouth, about 60 miles south of Cambridge. In an interview with a Russian TV station, his father said he'd recently urged Tamerlan, a community college dropout, to make sure his younger brother "studies well."
"I told him, 'You left school, got married too early, but the kid should finish [his education],'" said Anzor Tsarnaev, an auto mechanic. "Because this is life — those who don't study work a lot and work hard."
Fellow students described him as bright. Riley Baxter, 19, was his partner in a freshman engineering class, where they worked on circuit boards and lighting projects. "He was very smart and he was very good at what we were doing," Baxter said.
His recent academic performance, however, was lackluster. According to a university transcript reviewed by the New York Times, he had a B in Critical Writing but was failing many of his classes, with Fs in Principles of Modern Chemistry and Intro to American Politics.
On Twitter, Tsarnaev lamented the time he spent studying — he called it "a combination of the words student and dying" — and offered commentaries on his favorite TV shows, including "Breaking Bad." Humor is on full display.
"I hate these college desks, way too small to sleep on," one tweet said.
He drove a BMW, played intramural soccer for a team named Skillz FC and worked as a lifeguard, friends said. With high cheek bones and a mop of dark hair, he was considered something of a ladies' man.
Outside class, friends said, he rarely discussed academics. "It was always soccer or girls," Pariseau said.
Other topics he rarely broached: his Muslim faith, his Chechen roots and his older brother, whom relatives have said he revered.
In a social media profile, he describes his world view as "Islam" but his priorities as "Career and money," and he reportedly rejected an invitation to join the university's Muslim Student Assn. His brother began attending prayer services at a Cambridge mosque in 2012, but Tsarnaev rarely joined him, mosque officials said.
Tamerlan once said that "God said no alcohol," but the younger brother was known to enjoy drinking.
Tsarnaev only tweeted a few times about his faith, and the posts appear innocuous. "I don't argue with fools who say islam is terrorism it's not worth a thing, let an idiot remain an idiot," one said.
After the bombings, Tsarnaev returned to campus for three days. Sophomore Santo Dell Aquila, who lives in the same dorm as Tsarnaev, noticed that he bore a resemblance to pictures authorities released of the suspects and called the FBI.
Until then, the soccer-playing party guy had just blended in.
Times staff writer Molly Hennessy-Fiske in Boston contributed to this report, as did Times staff writers Seema Mehta and Laura J. Nelson and researchers Robin Mayper and Scott Wilson in Los Angeles.