The fatal shooting of a 64-year-old man by his estranged wife at their West Tisbury home Friday was a homicide during an act of self-defense, the district attorney said Monday.

Cape and Islands district attorney Michael O’Keefe said in a press release that the medical examiner found the cause of death for Kenneth R. Bloomquist was gunshot wounds to the chest sustained while assaulting his wife, Cynthia C. Bloomquist, with a shotgun. She will not be charged in shooting.

Mrs. Bloomquist, 63, was rushed to the hospital Friday morning after sustaining gunshot wounds in the leg area. She was listed in stable condition at Martha’s Vineyard Hospital, where she continues to recover.

On Monday, Mrs. Bloomquist’s lawyer, Sean E. Murphy, released a statement saying that Mr. Bloomquist broke into the locked home at 19 Skiffs lane Friday morning and shot Mrs. Bloomquist with a shotgun. He then produced a handgun and attempted to shoot her with it, the statement said, and during a “violent struggle” for the handgun, it discharged, hitting Mr. Bloomquist.

The statement said that Mrs. Bloomquist did not have any firearms in the home.

West Tisbury police were dispatched to the home at 7:48 a.m. Friday, responding to a 911 call placed by Mrs. Bloomquist, police said. A team of four officers went into the house and found both people upstairs. Two ambulances were called to the scene and the Island’s Tactical Response Team was also asked to respond.

Police said they found Mrs. Bloomquist in an upstairs bedroom with gunshot wounds to her torso, while Mr. Bloomquist was found deceased inside the house.

According to West Tisbury police sgt. Jeffrey (Skipper) Manter 3rd, Mrs. Bloomquist came to the West Tisbury police station after court hours on March 1 to request a restraining order against her husband.

The appropriate paper work was filled out, Mr. Manter said, but on-call judge Robert Kane denied issuing the order.

Mr. Manter had no comment about why Mrs. Bloomquist sought the order, or why the request was denied.

Mr. Bloomquist is listed as a partner in Harvard Images, an aerial photography company based in Harvard, Mass.

Mrs. Bloomquist is a former long-time employee of the Massachusetts Institute of Technology, where she worked from 1974 to 2010. Her most recent position there was as senior associate director for corporate relations.

According to the town assessor’s database, the couple purchased the West Tisbury property in 1981.

Mr. Manter, selectman Richard Knabel, and Cape and Islands assistant district attorney Laura Marshard all gathered outside the beige and white house at the top of Skiffs Lane, near Old County road, Friday morning as more than a dozen cars lined the street.

“This is a hugely unusual event for a town like West Tisbury,” Mr. Knabel said later. “We’re fortunate we have a very professional police force that is dealing with this, and has been dealing with this.”

“It’s unfortunate . . . we all wish it hadn’t happened,” he said. He said he did not know the Bloomquists, and declined any further comment.