NEW YORK, June 24: Betty Shabazz, the widow of American activist Malcolm X, has died of burns from a fire allegedly set by her 12-year-old grandson. She was 61.Shabazz suffered third-degree burns over 80 percent of her body in the June 1 fire at her Yonkers apartment. She had been listed in extremely critical condition since the day of the fire and underwent five operations to replace burned tissue with artificial skin.The grandson, Malcolm Shabazz, was arrested within hours and accused of setting the fire, reportedly because he was unhappy he had been sent to live with his grandmother and wanted to return to his mother, Qubilah Shabazz, in Texas. He is being held in juvenile custody.In 1965, pregnant with twins, she was in the audience at Harlem's Audubon ballroom with her four children when gunmen pumped 16 shots into her husband as he preached on stage.``Sister Betty came through the people, herself a nurse, and people recognizing her moved back, she fell on her knees looking down on his bare, bullet-pocked chest, sobbing, `They killed him,''' Alex Haley wrote in the book The Autobiography of Malcolm X.Shabazz went on to become a university administrator and spokeswoman for civil rights, and raised the couple's six daughters.``Millions of people look to her for some kind of understanding of the history of the struggle,'' said black activist and poet Amiri Baraka. ``She's the wife of one of the greatest African-American leaders of history.''Black activist Elombe Brath called Shabazz ``one of three major widows whose husbands were sacrificed to the struggle in this country,'' along with Coretta Scott King and Myrlie Evers-Williams.Doctors had said Shabazz might linger for weeks in critical condition. Burned skin is prone to infection and causes massive loss of fluids. It must be replaced if the patient is to live. Statistically, patients with Shabazz's injuries have a less than 10 percent rate of survival.Born in Detroit, Betty Shabazz studied at the Tuskegee Institute, Brooklyn state hospital school of nursing and Jersey city state college. She met her husband through the Nation of Islam and called herself Sister Betty X at the time.They married in 1958, when Malcolm was minister of Harlem's Mosque No. 7 and Betty was working as a nurse.