Abigail does blame Tituba, but then, to save herself, Tituba confesses that she has seen many witches with the devil. Abigail switches her focus, along with Tituba, and they both confess to Reverend Hale at the end of Act I that they conspired with the devil. Abigail claims that she signed the devil's book.
As a result of this shift of focus both Abigail and Tituba start naming and names, ultimately, Sarah Good and Goody Osburn are blamed. They are accused of being witches, of consorting with the devil.
"Abigail sees the enthusiasm with which Tituba’s accusations are received and decides to try the tactic herself. She, too, begins to name names. Finally, Betty also rises and joins in. The three women have discovered a way out of their predicament. Far from being punished for their behavior, they are now heroes of the community, chosen to help cleanse Salem. The naming of names is taken as an outward sign of their repentance and desire to be better Christians."