In an e-mail sent Tuesday morning, Yale Police Chief James A. Perrotti informed the Yale community of a robbery that occurred near Science Park on Mansfield Street by Tilton Street at 12:33 a.m. The victim — identified simply as a female friend of a university student — was walking alone when she was robbed of her cash by two men, one of whom was reportedly armed with a handgun. No injuries were reported. It has been five days since Perrotti last notified the University community of a crime.