New Haven crime came knocking on Yale’s backdoor Monday night.

A graduate student was robbed and assaulted by three unidentified females near the back gate of Pierson College on Park Street, Yale Police Department Chief Ronnell Higgins said in a campus-wide alert email soon after the incident. The victim, also a female, was thrown to the ground and assaulted by her assailants, resulting in minor injuries, YPD Spokesman Steven Woznyk said in an email Tuesday. Students and university officials said the incident’s proximity to Pierson and Davenport Colleges, as well as to undergraduate off-campus housing, is disconcerting.

“I find the incident pretty disturbing,” Davenport College Dean Craig Harwood said. “It’s our neighborhood ­— it’s right at our backdoor.”

Three students who live in Pierson and Davenport said they were worried about how close the mugging was to campus, and two said they would try to avoid walking by themselves on Park St. at night from now on.

In an email to Pierson students, Pierson College Master Harvey Goldblatt also called Higgins’s alert “disturbing,” and warned Piersonites to avoid walking alone. Harwood expressed similar concerns: all students should try to walk in well-lit areas and use Yale transportation whenever possible, he said.

Although the YPD has not made any arrests in connection with the incident, the department has begun to interview witnesses and review video footage of the area in hopes that investigators will find some leads in the investigation, Woznyk said.

In his email to the campus, Higgins said the YPD would be increasing patrols in the Park Street area in response to the mugging. In fact, the YPD has doubled its patrols in recent weeks in response to a rash of nearby incidents, Woznyk said. The additional patrols are concentrated in areas near the campus where there have been an overall increase in incidents, he added.

Because of the increased staffing levels, Woznyk said, officers on foot patrols were already on duty in the area when Monday night’s incident occurred.

Prior to Monday’s violent mugging, Yale saw a rash of shootings close to campus. Most recently, a March 23 shooting at Toad’s Place on York Street across from Trumbull College sent two men to the hospital.

“Our decisions on patrols and deployment are always informed by events and other relevant factors,” Higgins said in an e-mail to the News last week. “We have the ability to quickly devote effective resources to any area or crime issue around campus in coordination with the New Haven police.”

Other recent shootings include a March 14 shootout between two groups one block from Ingalls Rink, a March 18 shooting at the 100-116 block of Howe Street . where many undergraduates live, and a police chase-turned-shooting next to Yale offices at 25 Science Park.