Updated

A Massachusetts judge will hear from lawyers who want a teenager's confession to police that he killed his math teacher dismissed as evidence before his trial.

Philip Chism's lawyers say police coerced him into waiving his rights and making detailed statements about the murder.

A judge on Jan. 9 heard audio from police interviews with Chism's mother and testimony from the two police officers who initially detained him.

The officers said Chism had a bloody box cutter and women's underwear in his backpack when they found him walking along a road.

The 15-year-old has been charged as an adult with murder and aggravated rape in the October 2013 slaying of Colleen Ritzer, a teacher at Danvers High School.

He has pleaded not guilty. A hearing is being held Friday.