What if a police officer arrests someone because the officer doesn’t believe the person is telling the truth and there is evidence the officer is right? In District of Columbia v. Wesby the Supreme Court will decide whether, when the owner of a vacant house informs police he has not authorized entry, an officer assessing probable cause to arrest those inside for trespassing may discredit the suspects' claims of an innocent mental state. Facts similar to those in this case may not arise very often. But police officers must assess claims of innocence in numerous other instances (theft, assault, even homicide). Police officers arrested a group of late-night partygoers for trespass. The party-goers gave police conflicting reasons for why they were at the house (birthday party v. bachelor party). Some said “Peaches” invited them to the house; others said they were invited by another guest. Police officers called Peaches who told them she gave the partygoers permission to use the house. But she admitted that she had no permission to use the house herself; she was in the process of renting it. The landlord confirmed by phone that Peaches hadn’t signed a lease. The partygoers were never charged with trespass. The partygoers sued the police officers for violating their Fourth Amendment right to be free from false arrest. To be guilty of trespass the partygoers had to have entered the house knowing they were doing so “against the will of the lawful occupant or of the person lawfully in charge.” The partygoers claimed they did not know they lacked permission to be in the house.