A Wareham teenager pleads not guilty to charges of murder and assault in connection with the July stabbings of two brothers.

A spokesperson for the Plymouth District Attorney's Office says 18-year-old Bryan Grassie pleaded not guilty Monday in Wareham District Court, after he allegedly stabbed 18-year-old Brendan and 19-year-old Brian Mahoney on July 29.

Brendan died two days later at a Rhode Island Hospital, and Brian is still listed in critical condition. Witnesses told police that Grassie crashed a house party and stabbed the brothers after he was told to leave. Grassie was ordered held without bail until a pre-trial hearing on September 11.