A Seattle jury has convicted a 36-year-old man for killing six members of his ex-girlfriend's family on Christmas Eve 2007.

Jurors deliberated for less than two days before finding Joseph McEnroe guilty of six counts of first-degree murder with aggravating circumstances in King County Superior Court Wednesday.

McEnroe faces either life in prison without parole or execution, which jurors will decide in a second phase of the trial.

Prosecutors say McEnroe and his former girlfriend, Michele Anderson, shot her parents, brother, sister-in-law, 5-year-old niece and 3-year-old nephew.

They said the rampage in the small farming town of Carnation, east of Seattle, was clearly premeditated and that McEnroe believed Anderson had been slighted by her family.

McEnroe's defense lawyers argued that he was coerced by his former girlfriend and had argued for convictions of second-degree murder.

Anderson is also awaiting trial on the murders.