(ABC News) -- Boston University graduate student Lingzi Lu was the pride of her parents in China, but they are now engulfed in grief as she is identified as the latest victim of the Boston marathon bomber.
Lu, 23, was a mathematics and statistics student from China in the graduate class of 2015. Lu's parents described the death of their only child as a "dagger in our hearts."
The terrorist attack at the marathon killed three people and injured more than 170.
Speaking through sobs, Lu's father told ABC News in a telephone interview today from his home in northeast China, "This is an extremely painful time for our family."
He said the family has declined several interview requests because, "Every time we speak about this, it is like a dagger in our hearts."
Lu's father said he is in the process of obtaining a visa so he can travel to the United States to claim his daughter's body. She was the only child in a family that adhered to China's one-child policy, he said.
The U.S. Embassy in China said she was from Shenyang.
Lu reportedly attended Northeast Yucai School, considered one of the best high schools in Shenyang. The headmaster of the high school told Chinese media, "We are in shock."
Her family lives in one of the most developed and largest cities in China. Lu's father is a soft spoken but articulate man. Like many Chinese families, Lu's success in securing a spot at a university in the United States was a source of great pride for her parents and grandparents, her father said.
The student is said to have won academic scholarships to her prestigious high school and college. Her family supported her, as many Chinese families do, by saving every extra bit it could to go toward her education and experience in Boston, according to the Shenyang Evening News.
Meanwhile, hundreds of mourners held a vigil Tuesday night for Martin Richard, the youngest victim of the attack.
Friends, neighbors and even those who didn't know the Richard's family gathered at Garvey Park Tuesday night, each holding a candle in a cup and a U.S. flag.
Martin, 8, had an ice cream in his hand and was watching the marathon with his family when the twin bombs exploded.
"Everybody that was lost had their whole lives in front of them but really from an 8-year-old perspective, it's so different," Debbie Bickoff said at the vigil.
Bickoff was one of more than a 1,000 mourners who came to pay tribute to Martin and pray for his mother and sister, who are still in the hospital.
Martin's mother, Denise Richard, works as a librarian at the Neighborhood House Charter School, where he was a third-grader. Denise Richard is still in the hospital with a head injury.
Martin's younger sister, Jane, also remains in the hospital after she lost her leg. Jane, a dancer, was a first-grader at the same school where Martin's artwork still lines the hallways.
The boy's father, Bill Richard, released a statement Tuesday thanking friends, family and strangers for their support.
Staff members at the school are trying to cope with the loss before class resumes next week.
"We are going to be extremely strong. The joy of those voices will bring us back," Neighborhood House Charter School headmaster Kevin Andres said.
Dorchester, Mass., resident Lois Eames said it was important for her to attend the vigil because it's part of the healing process.
"This is what we do, we come together," she said. "You won't find another neighborhood like Dorchester in the whole world."
"Evil lives in this world but good will always overcome it," Eames added.
Joyce Allen and her daughter, Faith, said they couldn't believe the news about Martin's death when they first heard it.
"When they announced it, I was like, 'Is it this Martin?' and then I saw the last name and I thought it was very sad and how the family's going cope with that?" Joyce Allen said.
A few miles away from Dorchester, another vigil was held in Boston Commons Tuesday night where several hundreds gathered to remember Martin and the other two fatalities from the attack.
Krystle Campbell, 29, was identified Tuesday as the other fatality in the attack.
Campbell's parents, William Campbell Jr. and Patty Campbell, at first thought their daughter's friend had been killed, but later learned that it was their daughter who was the victim, according to ABC News' Boston affiliate WCVB.
The parents discovered their daughter was the one who had died when they were finally allowed to see the patient who had survived.
"I said, 'That's not my daughter. That's Karen! Where's my daughter?'" Patty Campbell told WCVB.
ABC News' Kaijing Xiao, Alyssa Newcomb, Anthony Castellano and Christina Ng contributed to this report.