diff --git a/programs/mutant-3/swen90006/passbook/PassBook.java b/programs/mutant-3/swen90006/passbook/PassBook.java
index 94e2dfdcd19284dafa914ed1214ff926ea3318da..37b366a1beaa62401cf3abbe6c78a92c954e02f0 100644
--- a/programs/mutant-3/swen90006/passbook/PassBook.java
+++ b/programs/mutant-3/swen90006/passbook/PassBook.java
@@ -145,7 +145,7 @@ public class PassBook
 	if (!passphrases.containsKey(passbookUsername)) {
 	    throw new NoSuchUserException(passbookUsername);
 	}
-	else if (sessionIDs.get(passbookUsername) != null) {
+	else if (sessionIDs.get(passbookUsername) == null) {
 	    throw new AlreadyLoggedInException(passbookUsername);
 	}
 	else if (!passphrases.get(passbookUsername).equals(passphrase)) {