BOSTON -- Four local police officers, including some Massachusetts state police troopers, have flown to England to investigate the murders of a Hopkinton, Mass., woman and her baby.

As the investigation enters a fifth day, police hope to speak with the father and husband, Neil Entwistle, whose family lives in the U.K.

NewsCenter 5's Sean Kelly reported that the Entwistle's lifestyle offered the appearance of a family living nicely. They leased a big house, he drove a BMW, and they took expensive vacations, but financial troubles may have been hidden beneath external appearances.

"There is information, at least superficial information, that leads us to believe they may have anticipated financial difficulties," Middlesex County District Attorney Martha Coakley said.

NewsCenter 5 reported what's been characterized as a potential online pyramid scheme linked to the couple. In recent months, more than $1,000 worth of adult entertainment software and business opportunities was sold on eBay, but never delivered, Kelly reported. It prompted angry reviews from customers. Prosecutors want to know more about how it relates to any money problems.

"It's potentially relevant in terms of why they did this, and is this a tip of an iceberg in some financial problems they had or faced," Coakley said.

Investigators said they know of no financial crisis and see no motives yet for the shooting deaths of Rachel, 28, and her 9-month-old baby Lillian. In Worksop, England, neighbors have not seen Entwistle's parents for several days. Prosecutors won't say whether Neil, 27, is staying there while in the country. People who knew him as a teenager said he was an ideal student.

"The things that are being said are stunning the staff here. They just can't understand where all this is coming from," said Brian Rossiter, principal of Valley Comprehensive School.

Entwistle is said to be cooperating with authorities as they develop a timeline. They believe he was in Massachusetts at the time of the murders. The medical examiners said Rachel and Lillian died between 1 a.m. Friday or early Saturday. Entwistle flew to England sometime late Friday or early Saturday.