University police responded to a request for a welfare check around 4:30 p.m. local time and found the student, who was identified as Andrea Rodriguez Avila, deceased in her room. Police also discovered an "unidentified male with a self-inflicted ... gunshot wound, who was not a member of the Rice community," school president Reginald DesRoches told the media.
According to Houston police, the shooting happened inside Jones College, one of 11 residential colleges on campus.
In a post on X, formerly known as Twitter, Rice University said its police department was investigating the potential homicide and requested all students, faculty, and staff to shelter in place.
Chief of Police for Rice, Clemente Rodriguez, confirmed police found a note "written by the suspect" at the scene, leading to their belief that the male shot Avila.
"In general terms, it was a lot about their relationship, and then obviously they were having a troubled relationship at this time," he said of the note, adding that officials believe it was a "dating relationship."
DesRoches said the "Rice campus is safe, and there is no immediate threat" to the community.
"And tonight, we will wrap our arms around our students," he added.
The shelter-in-place has since been lifted, but all classes and activities are canceled for the remainder of the day.
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ABC News contributed to this report.