BOSTON (AP) – The fatal shooting of a mother and her 9-month-old daughter in their Hopkinton home last week remains a puzzle, the lead prosecutor in the case said on Wednesday.

“It is a puzzle and we have a bunch of missing pieces,” said Middlesex County District Attorney Martha Coakley.

The bodies of Rachel Entwistle, 27, and her 9-month-old daughter, Lillian, were found in a bed in their home on Sunday evening. Neil Entwistle, 27, the British-born father and husband of the victims, remains a “person of interest,” Coakley said in an interview Wednesday.

Entwistle left the country some time late Friday or early Saturday, Coakley said, but she would not say where he went. The unemployed technology engineer has been in contact with police and the family of Rachel Entwistle in Carver, a suburb of Boston.

Coakley would not describe those conversations, or say who initiated the contact.

An autopsy and the fact that Rachel Entwistle called her relatives on Thursday has placed the time of their deaths between late Thursday and Saturday.

Autopsy results released Tuesday showed that the mother died of a gunshot wound to the head. The infant died of a gunshot wound to the stomach. Authorities initially suspected just one gunshot killed both mother and daughter because both had what appeared to be a torso wound.

It is unclear if they were killed before or after Neil Entwistle went overseas.

“We are keeping an open mind because we don’t know yet,” Coakley said. “He is clearly a person of interest, as any husband in a case like this would be.”

Neil Entwistle grew up in Worksop, about 90 miles west of Liverpool in central Britain, where his father, Clifford Entwistle, is a local elected official akin to a town councilor.

Rachel Souza grew up in Kingston, but spent a year studying abroad.

The couple met at a rowing club at the University of York in 1999, according to a posting by Neil Entwistle on the British Web site Friends Reunited.

“Getting married to the most amazing woman in the world this summer: Rachel,” Neil Entwistle wrote on Friends United.

The ceremony was in August 2003, and had their daughter Lillian in Britain in April 2005, according to the family’s Web site. A few months later the family moved to Massachusetts.

They initially stayed with relatives in Carver, Coakley said. The family had moved into their two-story colonial-style home in Hopkinton 10 days before mother and daughter were found dead.

Relatives told investigators that the Entwistles did not have a history of marital problems. He was looking for a job in the technology field; she had been a teacher but also was not working.

The couple’s Web site has been flooded with hundreds of condolences from friends, condemnations from strangers who assume Neil Entwistle is responsible for the crime, and poetry written by some of Rachel Entwistle’s former students.

“Helping me succeed in what I do,” one student wrote, “Never will there be a teacher as great as you.”