A British man whose American wife and daughter were found shot to death in their home was being quizzed by detectives at the U.S. Embassy in London on Friday.

Police said they drove Neil Entwistle, 27, to the embassy, but he was not under arrest.

"Neil Entwistle has agreed to voluntarily attend the U.S. Embassy in London to speak to American authorities in connection with the deaths of his wife and daughter," Nottinghamshire Police spokeswoman Rebecca Tomlinson said.

The embassy said Entwistle was speaking to U.S. and British law-enforcement officials, but would not indicate how long the questioning would last.

The bodies of Rachel Entwistle, 27, and her 9-month-old daughter, Lillian, were found in a bed in their home in Hopkinton, about 25 miles (40 kilometers) west of Boston, on Sunday evening. Both were killed by bullets from a small-caliber gun, according to the autopsy results.

Massachusetts officials have said Neil Entwistle, 27, was a "person of interest" in the case. He left the United States for Britain around the time of the deaths and was driven to London on Friday from his family home in Worksop in central England.

British police said Thursday that Entwistle was not a suspect and was being sought by authorities as a possible witness.

Middlesex District Attorney Martha Coakley has called Neil Entwistle, 27, a "person of interest" in the case. He left the United States for England around the time of the deaths. British police said Thursday that Entwistle was not a suspect and was being sought by authorities as a possible witness.

Two state police investigators and two Hopkinton police detectives are in England to interview Entwistle.

Coakley said the investigation is expected to go on for some time as authorities seek to speak to friends, family, former colleagues and other acquaintances in both the United States and United Kingdom.

In another development, officials at online auctioneer eBay Inc. said they were cooperating with law enforcement authorities investigating the murders.

Neil Entwistle had registered a business with eBay in England in April 2003, called srpublications, spokesman Hani Durzy told The Boston Globe. Customer feedback to the company, which sells software, had been overwhelmingly positive until the start of the new year when it turned sour.

Customers complained of undelivered materials and called the business a "scam." In response, eBay suspended the account on Jan. 9.

"What you can see is someone who, at least within the eBay universe, was acting as a good eBay citizen, until all of a sudden there was a period of 48 hours of bad feedback," Durzy said.

The autopsy and the fact that Rachel Entwistle called her relatives on Thursday has placed the time of their deaths between late Thursday and Saturday. Coakley said it's unclear whether Neil Entwistle left the country before or after they were shot.

The unemployed technology engineer has also been in contact with Rachel Entwistle's family in Carver, Mass., about 35 miles south of Boston.

Neil Entwistle grew up in Worksop, 150 miles north of London, in central England, where his father, Clifford Entwistle, is a local elected official akin to a town councilor.

He met Rachel Souza, a Kingston, Mass., native, in 1999 at the University of York, where she was spending a year abroad. They were married in 2003 and had their daughter in April, according to the family's Web site.

They moved to Massachusetts where 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.