why did mr. link deas and the others visit atticus?

Just a week later, events surrounding the trial begin to come to a head. First, a group of men pay a call to Atticus at his home. Jem and Scout watch from inside. The men make allusions to Tom being moved to the Maycomb jail the next day (Sunday), because the trial will occur on Monday. They are concerned that the "Sarum bunch" will cause some trouble, but Atticus thinks they won't do anything (such as a lynching) on a Sunday night. Mr. Link Deas warns Atticus that he has everything to lose from the trial, but Atticus says that he wants the truth to come out.