Prosecutors say 23-year-old Yao stabbed Deane Kenny Stryker, an aspiring doctor, in an unprovoked attack while she was sitting at a library table. After allegedly stabbing Stryker with a 10-inch hunting knife, Yao injured a 77-year-old man who jumped in and tried to help.
A Middlesex Superior Court grand jury indicted Yao on charges of murder, armed assault with intent to murder on a person over 60 years old, and assault and battery with a dangerous weapon on a person over 60.
Yao was arraigned on Friday. A judge ordered Yao held without bail. The next hearing in the case is scheduled for October 22.