Columbus Police is investigating seven armed robberies that occurred in the Ohio State campus area in the past 10 days.

One of the robberies was the subject of an OSU Police public safety notice. Two female OSU students were robbed outside 100 Chittenden Ave. on May 31 at 3:10 a.m. The armed suspect demanded the women’s cellphones and cash and threatened to rape and kill them. The suspect is described as a black man, 19-20 years old, baby-faced with dreadlocks, 5 feet 5 inches to 5 feet 6 inches and 140 pounds. He wore black pants, a blue and white plaid shirt under a gray hoodie and a black baseball cap turned backward.

The crime alert was issued last Thursday afternoon, nearly 12 hours after the robbery occurred. Crime alerts were not issued for any of the other crimes. University Police Chief Paul Denton said there is a policy for when to issue a timely warning, and only the crime on Chittenden fit the criteria for the alert.

“Warnings are not issued in every crime. They’re issued when a crime represents ongoing threats to the safety of people in the community,” Denton said Wednesday. “The crime on Chittenden was close to campus, so we decided to issue an alert.”

Denton said that putting alerts for every crime on campus would make people desensitized to the alerts themselves, and that “one alert was sufficient.”

Six other armed robberies of students have occurred in the campus area since May 28, NBC4 reported Tuesday. It is not known whether the robberies are connected. The robberies are listed by time and location:

May 28: 2:15 a.m. at E. 17th Avenue and Waldeck Avenue
May 30: 11:04 a.m. at 1622 North 4th Street
May 31: 3:10 a.m. at 100 Chittenden Avenue
May 31: 2:45 a.m. at East 12th Avenue and Summit Street
May 31: 11:42 p.m. at North 4th Street and East 13th Avenue
June 1: 10:45 p.m. at 65 W. Northwood Avenue
June 4: 11:18 p.m. at 161 W. Maynard Avenue

The Columbus Division of Police did not immediately return requests for comment.