BOSTON -- Sinking in debt and dissatisfied with his sex life, a British man killed his wife and baby daughter in the family's home, a Middlesex County Superior Court jury found on Wednesday.

Neil Entwistle, 29, was found guilty of two counts of murder in the first-degree in the shooting deaths of his wife, Rachel, 27, and their 9-month-old daughter, Lillian Rose, in the family's rented Hopkinton home in January 2006, reported WCVB-TV.

A jury of six men and six women weighed 12 days of testimony from family members, friends and investigators for six hours on Monday and five hours on Tuesday before coming back with a guilty verdict.

Neil Entwistle showed no emotion as the verdicts were read. He is scheduled to be sentenced at 10 a.m. Thursday.

While the defense tried to describe Entwistle as a devoted family man, the prosecution painted a picture of a man with a dark side who visited Web sites about killing and suicide and e-mailed women to arrange "discreet" relationships.

Neil Entwistle, a computer engineer, didn't have a job and faced mounting debt, including a monthly rental payment of $2,700 for the Hopkinton home, which the family had moved into just 10 days before the slayings, the prosecution said.

The day after the shootings, Neil Entwistle bought a one-way ticket and boarded a British Airlines flight out of Logan International Airport to his native England, where he was arrested two weeks later.

With its verdict, the jury rejected the defense team's claim that Rachel Entwistle killed her daughter before turning the gun on herself.

"I suggest that she might not even have known how to load (the gun) and handle it -- but he did," Assistant Middlesex District Attorney Michael Fabbri said, pointing at Neil Entwistle.

Neil Entwistle claimed he found his family dead in the master bedroom of the home after running errands on Jan. 20, 2006. To protect Rachel Entwistle's memory, Neil Entwistle returned the gun, a .22-caliber revolver owned by Rachel's stepfather, to his in-laws' home, the defense said. He then flew home to England, without calling the police or Rachel Entwistle's family.

In closing arguments, the prosecution said the murder-suicide theory didn't "make common sense."

"She was happy. She had no reason to commit suicide," Fabbri said.

Neil Entwistle did not take the stand and the defense rested without calling a single witness.