diff --git a/eth2/state_processing/src/per_epoch_processing.rs b/eth2/state_processing/src/per_epoch_processing.rs
index c4d1c69a23..f1ca42eda8 100644
--- a/eth2/state_processing/src/per_epoch_processing.rs
+++ b/eth2/state_processing/src/per_epoch_processing.rs
@@ -163,7 +163,8 @@ pub fn process_crosslinks<T: EthSpec>(
         let epoch = relative_epoch.into_epoch(state.current_epoch());
         for offset in 0..state.get_epoch_committee_count(relative_epoch)? {
             let shard = (state.get_epoch_start_shard(relative_epoch)? + offset) % spec.shard_count;
-            let crosslink_committee = state.get_crosslink_committee(epoch, shard, spec)?;
+            let crosslink_committee =
+                state.get_crosslink_committee_for_shard(shard, relative_epoch)?;
 
             let winning_root = winning_root(state, shard, epoch, spec)?;
 
diff --git a/eth2/state_processing/src/per_epoch_processing/get_attesting_indices.rs b/eth2/state_processing/src/per_epoch_processing/get_attesting_indices.rs
index 379159f4ef..1526c54beb 100644
--- a/eth2/state_processing/src/per_epoch_processing/get_attesting_indices.rs
+++ b/eth2/state_processing/src/per_epoch_processing/get_attesting_indices.rs
@@ -8,13 +8,12 @@ pub fn get_attesting_indices_unsorted<T: EthSpec>(
     state: &BeaconState<T>,
     attestation_data: &AttestationData,
     bitfield: &Bitfield,
-    spec: &ChainSpec,
 ) -> Result<Vec<usize>, BeaconStateError> {
-    let committee = state.get_crosslink_committee(
-        attestation_data.target_epoch,
-        attestation_data.shard,
-        spec,
-    )?;
+    let target_relative_epoch =
+        RelativeEpoch::from_epoch(state.current_epoch(), attestation_data.target_epoch)?;
+
+    let committee =
+        state.get_crosslink_committee_for_shard(attestation_data.shard, target_relative_epoch)?;
 
     if !verify_bitfield_length(&bitfield, committee.committee.len()) {
         return Err(BeaconStateError::InvalidBitfield);
diff --git a/eth2/state_processing/src/per_epoch_processing/validator_statuses.rs b/eth2/state_processing/src/per_epoch_processing/validator_statuses.rs
index 95cea17f49..169007154e 100644
--- a/eth2/state_processing/src/per_epoch_processing/validator_statuses.rs
+++ b/eth2/state_processing/src/per_epoch_processing/validator_statuses.rs
@@ -214,7 +214,7 @@ impl ValidatorStatuses {
             .chain(state.current_epoch_attestations.iter())
         {
             let attesting_indices =
-                get_attesting_indices_unsorted(state, &a.data, &a.aggregation_bitfield, spec)?;
+                get_attesting_indices_unsorted(state, &a.data, &a.aggregation_bitfield)?;
 
             let mut status = ValidatorStatus::default();
 
diff --git a/eth2/state_processing/src/per_epoch_processing/winning_root.rs b/eth2/state_processing/src/per_epoch_processing/winning_root.rs
index d64af31bbb..9a1da14d3f 100644
--- a/eth2/state_processing/src/per_epoch_processing/winning_root.rs
+++ b/eth2/state_processing/src/per_epoch_processing/winning_root.rs
@@ -77,7 +77,7 @@ pub fn winning_root<T: EthSpec>(
     let mut winning_root = None;
     for (crosslink, attestations) in candidate_crosslink_map {
         let attesting_validator_indices =
-            get_unslashed_attesting_indices_unsorted(state, &attestations, spec)?;
+            get_unslashed_attesting_indices_unsorted(state, &attestations)?;
         let total_attesting_balance =
             state.get_total_balance(&attesting_validator_indices, spec)?;
 
@@ -102,7 +102,6 @@ pub fn winning_root<T: EthSpec>(
 pub fn get_unslashed_attesting_indices_unsorted<T: EthSpec>(
     state: &BeaconState<T>,
     attestations: &[&PendingAttestation],
-    spec: &ChainSpec,
 ) -> Result<Vec<usize>, BeaconStateError> {
     let mut output = HashSet::new();
     for a in attestations {
@@ -110,7 +109,6 @@ pub fn get_unslashed_attesting_indices_unsorted<T: EthSpec>(
             state,
             &a.data,
             &a.aggregation_bitfield,
-            spec,
         )?);
     }
     Ok(output
diff --git a/eth2/types/src/beacon_state.rs b/eth2/types/src/beacon_state.rs
index f193b178fb..66375a1d2f 100644
--- a/eth2/types/src/beacon_state.rs
+++ b/eth2/types/src/beacon_state.rs
@@ -307,12 +307,12 @@ impl<T: EthSpec> BeaconState<T> {
     ///
     /// Spec v0.6.1
     pub fn get_attestation_slot(&self, attestation_data: &AttestationData) -> Result<Slot, Error> {
-        let target_epoch =
+        let target_relative_epoch =
             RelativeEpoch::from_epoch(self.current_epoch(), attestation_data.target_epoch)?;
 
-        let cc = self
-            .get_crosslink_committee_for_shard(attestation_data.shard, target_epoch)?
-            .ok_or_else(|| Error::NoCommitteeForShard)?;
+        let cc =
+            self.get_crosslink_committee_for_shard(attestation_data.shard, target_relative_epoch)?;
+
         Ok(cc.slot)
     }
 
@@ -361,25 +361,14 @@ impl<T: EthSpec> BeaconState<T> {
         &self,
         shard: u64,
         relative_epoch: RelativeEpoch,
-    ) -> Result<Option<CrosslinkCommittee>, Error> {
+    ) -> Result<CrosslinkCommittee, Error> {
         let cache = self.cache(relative_epoch)?;
 
-        Ok(cache.get_crosslink_committee_for_shard(shard))
-    }
+        let committee = cache
+            .get_crosslink_committee_for_shard(shard)
+            .ok_or_else(|| Error::NoCommitteeForShard)?;
 
-    /// Return the crosslink committeee for `shard` in `epoch`.
-    ///
-    /// Note: Utilizes the cache and will fail if the appropriate cache is not initialized.
-    ///
-    /// Spec v0.6.1
-    pub fn get_crosslink_committee(
-        &self,
-        epoch: Epoch,
-        shard: u64,
-        spec: &ChainSpec,
-    ) -> Result<&CrosslinkCommittee, Error> {
-        drop((epoch, shard, spec));
-        unimplemented!()
+        Ok(committee)
     }
 
     /// Returns the beacon proposer index for the `slot` in the given `relative_epoch`.