A 19-year-old man accused of shooting three former classmates to death at a house party in suburban Seattle has pleaded not guilty to murder charges.

The Daily Herald ( http://bit.ly/2bxwG39 ) reports Allen Ivanov entered the pleas during a brief hearing Monday afternoon in Snohomish County Superior Court.

Ivanov has been charged with three counts of aggravated murder and two counts of attempted first-degree murder. He is being held without bail.

Police say Ivanov was upset that his ex-girlfriend, Anna Bui, appeared to be moving on with her life after their recent breakup.

In addition to Bui, of Everett, Jordan Ebner, of Lake Stevens, and Jacob Long, of Everett, were killed in the July 30 shooting. They were all 19 and recent graduates of Kamiak High School in Mukilteo, a waterfront city of 21,000 people