The alleged sexual assault occurred at roughly 7:20 p.m.
"While walking, the suspect approached the victim. The suspect then forced the victim into a nearby bathroom where she was sexually assaulted. Officers responded, but were unable to locate the suspect," an incident summary said.
Police described the suspect as "a black male, 6 foot, with a muscular build who at the time was wearing a black shirt with red and gray trim and camouflage shorts." The suspect was not known to the victim, according to ASU police. The victim is not affiliated with ASU, a spokesperson for the university said.
It was the second sexual assault reported on the Tempe campus this year.
Police officials are still investigating whether campus surveillance cameras captured the incident.
In 2014, the school moved former campus police chief John Pickens to the newly created role of executive director of University Security Initiatives. Pickens had stepped down as police chief following the controversial arrest of a black ASU professor, a viral video of which prompted claims of racial profiling and excessive force in the department.
School records show that Pickens' job description included upgrading ASU's video surveillance system. Gaps in the system were exposed in December 2016 when a man armed with a knife briefly kidnapped a faculty member in her office. Cameras did not capture the incident.
At the time, ASU did not provide any documentation showing progress in Pickens' goal to expand the school's video camera system. Nor did spokesperson Gerardo Gonzalez provide any updates on Wednesday, telling Phoenix New Times, "The person who oversees this is not available today to provide me an update that I can pass on to you."
Gonzalez did not respond to a follow-up question on Thursday.
The alleged sexual assault this week also raises questions about the university's policy on public records requests for police reports. In February, ASU responded to a New Times request for police reports related to the 2016 arrest of a student arrested for shooting video of women using the restroom.
The university took three years to fulfill the request, an extraordinarily long turnaround for documents that police departments routinely provide within weeks or month.
University officials claimed ASU's policy was to wait until the Maricopa County Attorney's Office sent the school a disposition letter before releasing law enforcement records. That's a divergence from other Arizona police departments and a 1993 Arizona Supreme Court ruling that said agencies can't hide behind an "ongoing investigation" excuse to withhold records unless they can prove how sharing public information would impede their case.
ASU spokesperson Gonzalez appeared to backtrack on the school's hard line policy this week, saying in an email that police would provide a report to the media once it completed its investigation.