Tampa, FL -- Holding back tears, but not her frustration, Patricia Delorenzo described her sister Mary Frances Knight as incredibly intelligent and a thoughtful, loving mother.
"She was really the matriarch of our family. Sort of like the glue that held everybody together," she said.
Knight was one of 12 people murdered six weeks ago at the Navy Yard in Washington D.C.
The gunman, 34-year-old Aaron Alexis was also killed.
On behalf of Knight's family, her sister filed a claim Friday against the Navy and the Veterans Administration for $37.5 million.
"My sister would want me to fight for her and fight for the girls and me to fight for her and fight for the girls so that's what I'm doing," she said.
The claim alleges that the Navy and the VA should have known 34-year-old Aaron Alexis posed a threat, that he had sought help for psychotic episodes and that he had a record of gun violence.
Yet somehow, Alexis was allowed through the shipyard gates with a weapon.
"Mary Frances Delorenzo Knight had a right to expect that the Navy would protect her, and not let a rattlesnake into the tent," said the family's attorney Sid Matthew.
When asked what she would say to the Secretary of Defense, Patricia answered pointedly.
"Why did you let this happen? It's just a life wasted when all you could have done was had a simple gun check," she said.
Mary Frances, 51, was the mother of 2-grown daughters. Now 25 and 21.
She was always "10 steps ahead" of everyone, said Patricia.
In fact, in 2007 her sister had attached a letter to her will, a message in case anything ever happened to her.
"She said, 'I love you all, and I'll be watching over you, wherever I end up.'"
Delorenzo's attorney says this is not about gun control. What it is about, he says, is making sure Mary Frances Knight did not die in vain, and this sort of thing is not allowed to happen again.
By law, the Navy and VA have six months to respond to family's claim. If denied, they say they will file a lawsuit suit in Tampa Federal Court.