A female graduate student was allegedly attacked while walking on Putnam Avenue at approximately 9:05 p.m. Sunday, according to a community advisory e-mail issued Monday evening by the Harvard University Police Department.

The attack was allegedly part of an unarmed robbery.

According to the advisory, an unidentified male approached the student from behind while she was walking towards Peabody Terrace, grabbed her iPhone out of her hand and fled the area.

The student was not injured in the robbery, the advisory said.

The Cambridge Police Department is investigating the incident because it did not occur on Harvard University property.

HUPD sent a community advisory e-mail—the first of its kind since April—on Monday evening.

The department sends advisories directly to students, faculty, and staff at Harvard College and the Graduate School of Arts and Sciences, as well as to the deans of the University’s other schools and the Director of News and Public Affairs for the University. They also ask representatives to post the advisories in conspicuous locations on campus in addition to electronically forwarding them widely to students, faculty, and staff.

Prior to Monday’s notice, the last advisory was sent out on April 23, detailing an armed robbery that had occurred on Flagg Street and Putnam Avenue.

Since 2007, 13 such community advisories have been issued by the police department.

CPD public information officials could not be reached for comment yesterday evening.

—Staff writer Marianna N. Tishchenko can be reached at mtishch@fas.harvard.edu.