Neil Entwistle was planning a murder-suicide when he shot his wife and infant daughter with his father-in-law's gun in Hopkinton, according to Middlesex District Attorney Martha Coakley, who held a press conference on the matter this morning.
Entwistle, 27, was arrested this morning in England on two counts of murder and charges of illegal possession of a handgun and illegal possession of ammunition, prosecutors said.
Coakley said police believe he had financial problems and killed his wife, Rachel, 27 and his nine-month-old baby daughter Lillian on Friday morning, Jan. 20 in their rented home, before abandoning the plan to kill himself.
After that, Neil Entwistle allegedly returned the .22-caliber handgun to his father-in-law's home in Carver. Early Saturday morning on Jan. 21, he purchased a one-way ticket to London on British Airways and departed later that morning, Coakley said.
Under questioning from reporters, Coakley said the investigation looked into Entwistles business deals on e-Bay but concluded that disgruntled customers of his were not suspects in the case.
An arrest warrant was issued out of Framingham District Court last night.
Detectives from Scotland Yard took Entwistle, 27, into custody at 7 a.m. EST. Officials in London said Entwistle was taken into custody by the Metropolitan Police extradition unit at the Royal Oak tube station in London on a provisional extradition warrant issued by Bow Street Magistrates Court.
A week after the murders, Entwistle had refused to meet with Massachusettss investigators when they visited England.
Entwistle is now in custody at a London police station and will be brought before Bow Street Magistrates Court sometime this afternoon or tomorrow.
London Metropolitan Police said Entwistle's first court appearance would be Friday at Bow Street Magistrates Court, the customary venue for extradition cases.
(Material from Boston.com and Associated Press was used in this report.)