In an interview with KOMO News, the young woman's aunt and uncle said they want everyone to know what a good person she was.
"Very outgoing, she loved children," says the woman's aunt, Patricia Harding. "She was really making something of herself. She was just finishing up at community college."
The young woman's first name was Justine, but the family doesn't want her last name released yet.
Police say Justine's boyfriend, 27-year-old Dennis Clark, shot and killed her Sunday night in the unit where they lived together at Pinewood Apartments in Federal Way.
Family members say the 24-year-old victim had been dating Clark for five years and had a birthday coming up next month.
"My heart breaks every day thinking about my wife's sister and just the whole family and all the other families that have been shattered by this," says Justine's uncle Jason Harding."It's just unreal."
After shooting Justine, Clark then murdered three other people before he was shot to death by police as he was reaching for a weapon, officials say.
Two of the other three victims were identified Wednesday by the King County Medical Examiner as Ceasar A. Valdovinos, 23, and Roland L. Scobee, 62, of Federal Way. The third victim, believed to be a 47-year-old resident of Federal Way, has not yet been positively identified.
The shocking crime still has many people in the area stunned. A community meeting is scheduled for 6:30 p.m. Wednesday to answer questions.
One of the biggest questions for Justine's family is - what her future would have been.
"She really would have made a difference in this world," says Patricia Harding.
The shooting was the deadliest in the history of Federal Way.