Haruka Weiser had been missing for more than 12 hours, and her roommates were worried.

From her texts, they knew that the University of Texas at Austin freshman had left the school’s drama building around 9:30 Sunday night, and that she was walking back to their dorm along the creek that wound through campus.

But she never showed up in their room. The following morning, they reported Weiser’s disappearance to campus police. They hoped it would be nothing. On a campus of 50,000 students, people are thought missing all the time — usually, they decided to stay over at a friend’s house, or fell asleep at the library.

Instead, police uncovered a body in the campus creek. On Thursday, university officials announced it was Weiser’s.

The 18-year-old dance student was victim of a “horrifying and incomprehensible” killing, UT Austin President Gregory L. Fenves said, the first homicide on the Texas campus since 13 people were killed in the bell tower mass shooting 50 years ago.

“As a parent, this is my worst nightmare,” Fenves continued at the somber news conference Thursday. “… The unimaginable brutality against Haruka is an attack on our entire family.”

Police have identified a person of interest in the case: a 6-foot-tall black man seen riding through campus on a pink and red woman’s bike around 11 p.m. Sunday. Assistant Austin Police Chief Troy Gay said there’s no indication that he was a student or that he targeted Weiser specifically.

Authorities are offering a $15,000 reward for information leading to his identification and arrest.

No weapon has been recovered, and Gay would not say how Weiser was killed, though he confirmed that her autopsy showed she was assaulted.

UT Austin has not seen a slaying on campus since 1966, when a 25-year-old engineering student Charles Whitman climbed to the top of the university’s bell tower and began firing indiscriminately at people below. Whitman took sixteen lives, including those of his wife and mother and the unborn child of a pregnant woman who was shot in the stomach (the woman survived) before he was shot and killed by police.

Weiser’s death has left the campus palpably shaken. On Tuesday, after the teenager’s body was found, the school stationed extra police officers around campus, including some from the Austin Police Department. It also provided shuttle vans and police escorts for students moving around campus after dark. Fenves added that the Department of Public Safety will undertake a review of campus security to see how it can be improved.

“To our students, you expect and deserve to be safe on our campus,” he said.

Hundreds of students gathered Thursday evening for a vigil in Weiser’s honor. Organizers handed out black ribbons and notecards on which people could write messages to their slain classmate. The crowd fell quiet for a moment of silence, and the lights on the 300-foot tower dimmed.

“There is so little to say. No one has the words that will work,” said Brant Pope, chair of the department of theater and dance, according to campus newspaper the Daily Texan. “We are together as a community for Haruka and for ourselves. We gather because life is precious — Haruka was precious, and precious to us.”

An online fund set up for Weiser’s family had raised nearly $2,000 in a matter of hours. Many of the contributions came from students, in $15 and $20 increments.

“She had a beaming smile we all came to know and love, and her zeal and charisma was unparalleled,” the fund’s creators wrote of their classmate.

Weiser, a freshman from Portland, Ore., was a talented and beloved member of the university’s dance program. Program head Charles Anderson spoke at the vigil of the day he first saw Weiser, during the National High School Dance Festival two years ago.

“We immediately turned to each other and said ‘Her — we have to have her,’ ” Anderson said, according to the Daily Texan. “We spent the remainder of that year like football coaches trying to get her to come here.”

In a statement published by the school, Weiser’s family said their daughter was thrilled to attend UT’s dance program. But her passions were broad-ranging. They wrote that Weiser planned to focus on medicine and visit family in Japan this summer.

Now her family is left to make sense of dreams horribly cut short.

“Although Haruka loved to perform on stage she never sought the spotlight in her daily life,” Weiser’s family wrote. “Perhaps the last thing she would want is to be the poster child for any cause. And yet, as we struggle to understand why she was killed, if her death can somehow make it safer for a young woman to walk home, if it will prevent another assault or murder, then at least we could find some meaning behind an otherwise senseless and tragic death.”

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