Saira Khan, sister San Bernadino attacker Syed Farook, has now spoken for the first time since finding out her brother was accused of massacring 14 people.
She told CBS she was angry at her brother for leaving his six month old daughter behind, and "deeply saddened" by his actions.
Describing both Farook and his wife as "shy and quiet", she said she has asked herself repeatedly if she could have stopped the shooting.
"I ask myself if I had called him that morning or the night before, asked him how he was doing, what he was up to. If I had any inclination maybe I could have stopped it."
While Saira says she need time to mourn "just like everybody else", her husband said he felt responsibility to speak out against Farook's actions.
"I love this country, I love the people. And I felt responsibility to tell to tell this to the people...."
"What he did to his own family, to his daughter, to the innocent people there. No, I won't forgive him."