According to Wikipedia, in 1706, at the age of 27, Ann wrote, "I desire to be humbled before God for that sad and humbling providence that befell my father's family in the year about ninety-two; that I, then being in my childhood, should, by such a providence of God, be made an instrument for the accusing of several people for grievous crimes, whereby their lives was taken away from them, whom, now I have just grounds and good reason to believe they were innocent persons; and that it was a great delusion of Satan that deceived me in that sad time, whereby I justly fear I have been instrumental, with others, though ignorantly and unwittingly, to bring upon myself and this land the guilt of innocent blood; though, what was said or done by me against any person, I can truly and uprightly say, before God and man, I did it not out of any anger, malice, or ill will to any person, for I had no such thing against one of them; but what I did was ignorantly, being deluded by Satan.
And particularly, as I was a chief instrument of accusing Goodwife Nurse and her two sisters, I desire to lie in the dust, and to be humble for it, in that I was a cause, with others, of so sad a calamity to them and their families; for which cause I desire to lie in the dust, and earnestly beg forgiveness of God, and from all those unto whom I have given just cause of sorrow and offense, whose relations were taken away or accused."
The "evidence" given in the witch trials included the accusers saying they "saw" the accused afflicting them, so you would think they normally would know whether they were lying or not.
She had been influenced and encouraged to accuse certain people by her mother, Ann Putnam Sr. The Puritans had a tendency to blame Satan for everything.
What the accusers allegedly "saw" were the "specters" of the accused afflicting them. Once the ministers began questioning the validity of "spectral evidence," the trials came to an end. Thought it concentrates on the alleged "ghosts" of the Salem witches, there is an excellent account of the trial in an article called "Ghosts of the Salem Witch Trials," which states:
Mary Herrick, now terrified more by the prospect of another ghostly visitation than being accused of witchcraft, confessed what had transpired to the ministers. Hale, certain his wife was no witch, reconsidered his position on spectral evidence and later expressed contrition for “unwittingly encouraging ... the sufferings of the innocent.” Other ministers followed suit and it was determined spectral evidence could not be considered as proof of trafficking with the devil. Without spectral evidence, there was no evidence at all against the majority of the accused and the witch madness came to an end.