-- A massive manhunt is underway at the University of Texas at Austin to find the person responsible for the death of a freshman student, and police are asking for the community's help.
Haruka Weiser, 18, a first-year theater and dance major, was last seen leaving a university drama building Sunday night. Her body was discovered in a campus creek Tuesday.
The Austin Police Department said Weiser was a victim of assault. University President Gregory L. Fenves described the attack as "unthinkable brutality."
Police have released surveillance video showing a man on campus with a backpack and bicycle that night who's considered to be a person of interest.
"We’re pretty confident that the man you see in the video, who appears to be in his early 20s, late teens, is definitely somebody that’s very much of interest to us," Austin Police Chief Art Acevedo told ABC News. "We’re very confident ... that this is the person that when we bring him in, that it will be the person responsible for this act."
He added: "We’re very hopeful that the public, people around Austin, people around UT saw him and will be able to come forward and give some information on him."
Acevedo said it is unclear if Weiser and the person of interest knew each other.
"Unfortunately, you think about these young people coming to college -- there’s 50,000 folks there. There’s a lot of questions that we need to answer," Acevedo said. "But we owe it to the Weiser family, the University of Texas, the student population and the community of Austin to bring closure to this case and bring that [possible] suspect to justice."
While the person of interest remains at large, Acevedo said that UT Austin is a very safe campus and that Austin is one of the safest cities in the nation.
"We have one of the lowest violent crime rates in this nation, But having said that, it’s still a big city," he said. "As safe as it is, things do happen so situational awareness is really important at night."
Acevedo said Weiser's death marks the first homicide there since the UT Tower massacre in the summer of 1966, in which a man opened fire from the top of the campus tower, killing 16 and wounding many others.
Thursday evening, hundreds gathered on UT Austin's East Mall to mourn the slain freshman. A moment of silence started the vigil, followed by speeches from students, administrators and faculty members.
Grief counselors were also on hand as organizers distributed black ribbons and note cards for writing messages.
Weiser's family hopes this incident will help prevent another loss of life.
"As we struggle to understand why she was killed, if her death can somehow make it safer for a young woman to walk home," her family said in a statement. "If it will prevent another assault or murder, then at least we could find some meaning behind an otherwise senseless and tragic death."
Austin Police Department Assistant Chief Troy Gay described the campus as "active" at the time the person of interest was seen on campus, with cyclists and students appearing near him. Police are offering a $15,000 reward for information leading to an arrest.