Why is John Proctor arrested?
In act 3, John Proctor comes to the court with a deposition containing nearly a hundred signatures of people who are willing to serve as character witnesses for Elizabeth Proctor, Martha Corey, and Rebecca Nurse. This is an act that does not endear him to the authorities. When Proctor continues to push for his wife's release, he is forced into the position of confessing his adulterous affair with Abigail Williams. This is enough to get him arrested (and executed under Salem's law), but it is not until Mary Warren accuses him of witchcraft that Proctor is actually arrested. Mary Warren points at John Proctor in the courtroom and says, "You are the devil's man." Because Proctor is frustrated at the illogicality of the proceedings (particularly the admission of spectral evidence) and the fact that the girls' accusations are condemning innocent people, Proctor yells, "God is dead!" and the marshals take him into custody.