Neil Entwistle was convicted Wednesday of murdering his wife and baby daughter.

Jurors found the British man guilty of first-degree murder in the killings of his 27-year-old wife Rachel and 9-month-old baby girl Lillian Rose, rejecting the defense's argument that Rachel Entwistle had killed the child and herself.

Entwistle, 29, closed his eyes and shook his head slightly upon being found guilty of two counts of first-degree murder in the shooting deaths of mother and child in the family's suburban Boston home. He also was convicted on two weapons charges.

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His parents immediately asserted their son's innocence and said he had not received a fair trial. His lawyers said they planned to appeal.

"We know that our son Neil is innocent, and we are devastated to learn that the evidence points to Rachel murdering our grandchild and then committing suicide," his mother, Yvonne Entwistle, said outside the Middlesex District Courthouse.

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"I knew Rachel was depressed. Our son will now go to jail for loving, honoring and protecting his wife's memory," she said.

Jurors reached their verdict after a day-and-a-half of deliberations.

Prosecutors argued that Entwistle was in debt and dissatisfied with his sex life when he fatally shot his family in their rented Hopkinton, Mass., home in 2006. After the shootings, he fled to his native England.

The defense did not put on any witnesses. Instead, Entwistle's attorney claimed Rachel Entwistle shot Lillian and then killed herself while the two snuggled in bed.

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Entwistle acknowledges not calling police after he said he found their bodies, and said he returned the .22-caliber gun used to kill them to his father-in-law's house 50 miles away in an effort to preserve her honor.

His father, Clifford, said his son's fate was sealed even before the trial.

"We will continue to fight for our innocent son with the hope that one day justice will prevail and our little granddaughter, Lillian, will rest in peace," he said.

Rachel Entwistle's family did not immediately comment.

Sentencing was scheduled for Thursday morning.

Under Massachusetts state law, Entwistle must be sentenced to life in prison without the possibility of parole.

The Middlesex Superior Court jury deliberated Tuesday for about six hours. They told the judge they had reached a verdict after 2 p.m. Wednesday.

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The Associated Press contributed to this report.