BOSTON — Lu Lingzi learned Sunday that she had passed a major exam for her studies at Boston University.
The next morning, the test and a major project behind her, the 23-year-old Chinese graduate student and two friends headed over to watch the Boston Marathon. They chose spots near the finish line.
Hours later, two bombs exploded there.
It was midafternoon in Boston, the middle of the night in China. As hours ticked by and Lu still hadn't called, her parents and grandparents grew panicked. Online messages began to fly between Boston and China.
"Lingzi, where are you now?" her roommate wrote on the microblogging platform Weibo. "I know you get lost so easily. Don't worry. We will find you."
About a half-dozen international students from China spent about seven hours Tuesday searching for her in Boston-area hospitals. Friends learned that Zhou Denling, who had been with Lu at the finish line, had been hospitalized. But the students could find no official news of Lu.
Friends would learn later Tuesday night that Lu was in fact one of three people killed by the explosions. The others were Martin Richard, 8, of Dorchester, Mass., and Krystle Campbell, 29, of Arlington, Mass. More than 170 people were injured.
Cheering on the runners was the latest cultural touchstone Lu had embraced since moving to Boston in August to enroll in BU's actuarial science program, the study of risk. She had posted enthusiastically on social networking websites about life in the United States, gushing about friends, shows — and most of all, food. Homesick for familiar Chinese dishes, Lu sought out dumpling restaurants in New York and a Sichuan restaurant in the Boston suburbs. She bought a waffle iron. She baked her first cake.
Her comments were invariably cheerful and positive, often punctuated by exclamation marks. "I love the Charles River at night!" she wrote. "Chocolate makes me happy."
Professors in BU's mathematics and statistics department remembered Lu as a smart, hard-working student in the top quarter of her class. The statistics department is a close-knit community, they said, and many knew Lu well.
"We lost a promising young scientist," said Tasso Kaper, the department chairman. Lu was smart and energetic, he said, and had begun to look into internships.
On the BU campus, Carl Wu, an economics grad student, placed a bouquet alongside a dozen others outside Marsh Chapel. It was a symbol of sympathy for Lu's parents, who he said may have lost their only child, given China's one-child policy.
The flowers were also a symbol of solidarity with Chinese students who come to the U.S. in search of an education. While Wu didn't know Lu well — he had met her only at parties, and they had mutual friends — they both shared the same experience: leaving their families, traveling thousands of miles from home.
"For everyone, these are not easy things," said Wu, 23. "It's painful for us, for all Chinese students."
Originally from Shenyang in northeastern China, Lu was a top student at her high school and attended the Beijing Institute of Technology. "The girl is very smart," Yang Yongkun, a high school teacher, was quoted as saying in Chinese media. "Although she graduated some years ago, I still remember her."
In her Weibo photograph, Lingzi is shown in a cream-colored, lace-trimmed dress, her hair combed demurely to one side. The most adventurous touch was her turquoise-colored fingernails. She painted her nails, she wrote, to prevent herself from biting them. She also posted pictures of her two dogs and a Teddy bear she kept on her pillow.
By midday Wednesday, more than 10,000 Chinese had commented on the last photograph she had posted on Weibo: a plate of vegetables and bread, next to a smiley face and a caption reading, "My wonderful breakfast!"
"Rest in peace!" wrote one visitor. "Hope you can be happy in Heaven and continue to make delicious food on the other side."
Tangel reported from Boston, Demick from Beijing and Nelson from Los Angeles.