Who are Ann and Thomas Putnam?
Ann and Thomas Putnam are referred to in The Crucible as Mrs. Putnam and Putnam. This is a land-owning couple who were extremely interested in what went on in the church. Their motivation likely sprung from Ann's brother-in-law being turned down for the position of minister at the town's church. Feeling an obvious allegiance to family, since that point, the Putnams are suspicious of what occurs in the church.
Their reputation in the town isn't a good one. Although Thomas' father fought Indians and was really rich (a great lot of which I am sure Thomas acquired), Thomas didn't have the same appeal. He and his brother tried to have a different minister jailed, Thomas tried to break his father's will, and many people have had false accusations heaped on them in Thomas' voice.
The two of these folks tend to accuse others in the town of witchcraft-like behavior. This is a great one to claim because it is hard to prove against it...
A note on Ann: She has lost several babies in childbirth or as infants. Interesting, huh?