diff --git a/src/event_auth.rs b/src/event_auth.rs
index 0f6b6942..a2e62e34 100644
--- a/src/event_auth.rs
+++ b/src/event_auth.rs
@@ -336,6 +336,7 @@ pub fn valid_membership_change<E: Event>(
 
     let key = (EventType::RoomMember, target_user_id.to_string());
     let current = auth_events.get(&key);
+
     let current_membership =
         current.map_or(Ok::<_, Error>(member::MembershipState::Leave), |pdu| {
             Ok(serde_json::from_value::<room::member::MembershipState>(
diff --git a/src/lib.rs b/src/lib.rs
index ac621b1b..ab4f2681 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -510,7 +510,15 @@ impl StateResolution {
             for aid in &event.auth_events() {
                 if let Ok(ev) = StateResolution::get_or_load_event(room_id, &aid, event_map) {
                     // TODO synapse check "rejected_reason", I'm guessing this is redacted_because in ruma ??
-                    auth_events.insert((ev.kind(), state_key.clone()), ev);
+                    auth_events.insert(
+                        (
+                            ev.kind(),
+                            ev.state_key().ok_or_else(|| {
+                                Error::InvalidPdu("State event had no state key".to_owned())
+                            })?,
+                        ),
+                        ev,
+                    );
                 } else {
                     log::warn!("auth event id for {} is missing {}", aid, event_id);
                 }