Updated

A Boston man killed his pregnant girlfriend and her sister before turning the gun on himself after a fight broke out, allegedly over the unborn child’s name, the Boston Globe reported Tuesday.

Joseph Cummings, 51, shot dead his longtime girlfriend and nail salon owner Kimberly Nguyen, 35, during the fight in their second-floor master bedroom Monday night.

"There may have been an argument over the name of the child,'' Essex District Attorney Jonathan Blodgett was quoted by the Globe as saying.

The woman’s sister, Lily Nguyen, a 29-year-old Wesleyan University graduate and aspiring medical student, heard the shots and jumped out of a second-story window. Cummings shot her as she tried to run away, and then turned the gun on himself in the bedroom.

Kimberly Nguyen’s 12-year-old daughter from another relationship was home at the time of the killings. She managed to escape and called 911 from a neighbor’s home.

"This is another needless, senseless domestic violence tragedy ending in three deaths,'' Blodgett said.

The surviving 12-year-old was reportedly staying with relatives at an undisclosed location.