( CNN ) -- A Massachusetts high school student accused of raping and killing his math teacher has been indicted on charges he attacked an employee at a youth services facility , a district attorney 's office announced Wednesday . According to the Suffolk County District Attorney 's office , on June 2 , Philip Chism followed a 29-year-old female employee into the bathroom at the Metro Youth Services facility in the Boston neighborhood of Dorchester and physically assaulted her . `` Co-workers heard her cries for help and interrupted the assault , '' the district attorney 's office said . On Wednesday , Chism , 15 , was charged with attempted murder by strangulation , assault with intent to murder , kidnapping and two counts of assault and battery with a dangerous weapon . Chism remains in custody . Suffolk County Juvenile Court has not set an arraignment date for these charges . His lawyers did n't answer calls from CNN when the new allegation surfaced last month . The teenager is accused of killing his algebra teacher , 24-year-old Colleen Ritzer , last October at Danvers High School , about 20 miles north of Boston . Police and prosecutors say he used a box cutter to kill Ritzer in a girls ' bathroom . Chism pleaded not guilty to aggravated rape , robbery and murder charges in January . He is being tried as an adult . Prosecutor : Suspect in teacher 's killing planned attack on youth counselor . Teen admitted killing popular teacher , affidavit says . Teen pleads not guilty to rape , murder of high school math teacher .
Philip Chism is charged with attempting to kill a youth services worker . Teen accused of attacking the female employee in the bathroom . He is charged with raping and killing his algebra teacher . Score: 6