Police officials are investigating "bleach-bomb" attacks on four minority students from the University of Texas at Austin.

All four students have alleged that they have been victims of "bleach-bomb" attacks, in which bleach-filled balloons were thrown while they were walking on the campus.

The assaulted students were either Asian or of African-American origin and it is alleged that they were targeted for their race.

The incidents took place between June and September. However, the students did not file any complaint until they were urged by the chief campus police officer, reported the Los Angeles Times. "They did not file reports when the alleged incidents happened. Our chief of police heard about the incidents through the grapevine and sought out the victims," to file reports, Cindy Posey, spokeswoman for campus police, told the Los Angeles Times.

Earlier on Tuesday (Sept. 2) a group of students, including the four victims, gathered under the statue of Martin Luther King Jr. in the campus and joined a rally in support of the victims. They protested against the alleged racial attacks.

Taylor Carr, a sophomore anthropology student at UT, said she was hit by a bleach balloon from a high-up apartment balcony while walking in the West Campus. She alleged that she was targeted as she was black, reported The Horn.

"It is people of color they are attacking in West Campus," The Horn quoted Carr as saying.

"Until we put pressure on the university to [protect] us, these events are going to keep happening," she said.

The Greek community in UT Austin has been criticized for conducting race-themed parties, where students indulge in wearing clothes that are linked to a minority group.

Recently, members of two sorority big groups apologized for organizing a party called "Fiesta" wearing t-shirts with captions that read "Illegal" and "Border Patrol."