Despite three witnesses and several changes to her story, woman acquitted of murder

Story here. Excerpt:

'Ebony S. Mack was found not guilty Friday of killing a mother of four in a street-corner slaying that helped launch Rochester's Zero Tolerance anti-crime initiative.

Monroe County Court jurors acquitted Mack of second-degree murder, first-degree manslaughter, first-degree gang assault and second-degree gang assault in the death of Latasha Shaw, who was beaten and stabbed by a mob at Dewey and Driving Park avenues on Sept. 29, 2007.
...
A mob of 10 to 20 people stormed from the porch of a home occupied by Mack's mother and engulfed Shaw. As two of her daughters and her sister watched, Shaw was pummeled with sticks and bats, stabbed with a kitchen knife and left dying face-down in a puddle of blood.
...
Three witnesses, including Shaw's 12-year-old daughter, who was 10 when her mother was slain, identified Mack as the woman they saw plunge a knife into Shaw's chest. But the defense questioned the credibility of the witnesses, two of whom got breaks from the prosecution on criminal charges because of their testimony against Mack.
...
During an eight-hour-long interrogation by homicide investigators, Mack changed her story several times. At first insisting she was at work when the slaying occurred, she later admitted participating in the earlier fight involving Shaw's daughter and said she saw the mob engulf Shaw during the fatal fight.'