Jane Boleyn, Lady Rochford: Villain or Victim?

Jane Boleyn, Lady Rochford served the first five queens of King Henry VIII and counted Anne Boleyn as her sister-in-law. Unfortunately, she has been perpetually vilified as the chief source of her husband and sister-in-laws demise, and yet what is the evidence to support this theory? And how did Jane become so embroiled in the scandal of Katheryn Howard's love affairs that she also lost her head to the axeman in 1542?