When the girls bring Sophia home from the trial, they sit on the couch. You can see studio lights and other equipment in the reflection from Sophia's glasses.
The police case against Sophia rests entirely on the "deathbed confession" of Mrs. Hargrove. With certain limited exceptions, statements by a witness who is unavailable to testify at trial are inadmissible hearsay, even if given under oath. A criminal defendant has an absolute right to face and cross-examine any witness called against them, and any testimony that does not allow for cross-examination can't be used. The Hargrove confession would have been ruled inadmissible at the first hearing and the case dismissed.
It is never explained why the fire marshal would have been on the take.