BOSTON -- The shooting deaths of a Hopkinton woman and her 9-month-old daughter are now at the center of an international investigation.

NewsCenter 5's Janet Wu reported that police in England said Neil Entwistle is not a suspect in the murder of his wife and daughter. Local authorities echo the statement, calling Entwistle a "person of interest."

Two state police investigators and two Hopkinton detectives arrived in England Thursday. While Scotland Yard has declined comment, a spokeswoman for police in Nottinghamshire County, where Neil Entwistle's parents live, issued a statement Thursday.

"Neil Entwistle is not a suspect. He is being treated by the U.S. authorities as a potential witness. There are no extradition proceedings in relation to him. On that basis, police in England and Wales have no legal powers to take executive action. In these circumstances, it is not our role to comment on his whereabouts," said Rebecca Tomlinson said.

Meanwhile in Massachusetts, Entwistle's car remains at Logan Airport where Neil Entwistle left it late Friday or Saturday morning before flying to England. Police believe his wife and daughter were killed about the same time he left the country.

Middlesex County District Attorney Martha Coakley released a statement Thursday that called this "a very active investigation, operating 24 hours a day at this time." While she gave few specifics, she said they are making "consistent progress on several fronts, but there are still many pieces of this puzzle missing."

Meanwhile, Newscenter 5 has been in contact with several people who have recently done business with Neil or Rachel Entwistle through eBay. One British customer who failed to receive software he purchased from the Entwistles said he eventually received a refund and an apology from someone who claimed to be Rachel Entwistle. He also said he was recently contacted by police about that transaction.

Coakley confirmed in her statement Thursday that the investigators are in England to interview many people.

"There are a number of individuals, friends, family, former colleagues and other acquaintances -- in both the United States and the United Kingdom, with whom police are interested in speaking as the investigation proceeds," the statement said. "It is important to note that no arrest warrants have been issued."

Coakley also emphasized that her office does not consider the deaths to be random, noting there was no sign of forced entry at the Hopkinton home.

Relatives told investigators there was no history of marital problems. The Entwistles had been married for three years.