A lawyer for a British man accused of killing his wife and baby complained Monday that he would have difficulty picking an impartial jury because a judge barred him from asking potential jurors their feelings about the man's alleged use of Internet sex sites.

Neil Entwistle, 29, is charged with fatally shooting his 27-year-old wife, Rachel, and their 9-month-old daughter, Lillian Rose, in their Hopkinton home in 2006. He has pleaded not guilty.

On Monday, Entwistle's lawyers and prosecutors began the process of weeding through 170 potential jurors in Middlesex Superior Court. A jury of 12 jurors, plus four alternates, will be selected for the trial, which is expected to last about three weeks.

Entwistle's lawyer, Elliot Weinstein, complained that Judge Diane Kottmyer was not allowing the defense to fully probe potential jurors about what they had read and heard about the case in news reports.

Weinstein also sought to ask, but the judge wouldn't allow, questions to potential jurors about how they would view Entwistle's alleged visits to Web sites that featured escort services and connected people looking for sex. Prosecutors want to present evidence that Entwistle trolled the Internet looking for sex in the weeks before the killings.

Weinstein said hearing about the Web sites could prejudice the jury against Entwistle because prosecutors plan to use his online history to argue he was motivated to kill his wife in part because he was unhappy with his sex life.

Entwistle told police he returned home from errands on the morning of Jan. 20, 2006, to find his wife and daughter dead. Their bodies were discovered curled up in bed together in their rented Hopkinton house two days later. Entwistle said he flew home to England after the killings to be comforted by his parents.

Prosecutors, however, say Entwistle became despondent about his family's deteriorating financial situation and dissatisfied with his sex life. They accuse him of shooting them and then fleeing the country.

According to a summary of the case filed in court by prosecutors, Entwistle's computer records showed he exchanged e-mails with a woman he met on a Web site called Adult Friend Finder. He told the woman he was in a relationship "but looking for a bit more fun in the bedroom" and "a very discrete relationship just for fun."

The case has received widespread media attention on both sides of the Atlantic. It was clear Monday that many potential jurors had read or heard about the case.