The tragedy surrounding the Fourth of July car crash on the Vineyard deepened when a second victim died at a Boston hospital Tuesday night.

According to a family friend, Seth Jones, 26, of Dummer, N.H., died early Tuesday evening. His death was confirmed by a spokesman at Beth Israel Deaconess Medical Center.

Mr. Jones was taken off life support and was surrounded by family and friends, Melanie Devoid, the family friend, told the Gazette.

Mr. Jones’s girlfriend, Heather Laflamme, 21, of Berlin, N.H., died on July 7 after sustaining injuries in the two-car crash on Barnes Road on the afternoon of July 4. Both were passengers in the back seat of a Jeep Wrangler driven by Mr. Jones’s father, Thomas C. Jones, 51. His mother, Margaret Jones, 51, was a passenger in the front seat. Mrs. Jones was listed in good condition at Beth Israel last week.

The other car involved was a 2012 Volkswagen Tiguan driven by Benjamin T. Johnson, 19, of Cambridge.

The accident remains under investigation by state police.

Funeral services were held for Ms. Laflamme over the weekend.

Mr. Jones, one of four brothers, was a Marine who served active duty in Iraq and Afghanistan. His uncle, Donald Antonelli, told the Gazette that Mr. Jones had been working as an apprentice welder at the Portsmouth Naval Yard.

Mr. Antonelli said last week that there had been an outpouring of support for Mr. Jones from the Berlin, N.H. community and from fellow Marines.