diff --git a/beacon-chain/attestation/BUILD.bazel b/beacon-chain/attestation/BUILD.bazel
index 75e4df87f..e0e370dd9 100644
--- a/beacon-chain/attestation/BUILD.bazel
+++ b/beacon-chain/attestation/BUILD.bazel
@@ -38,6 +38,8 @@ go_test(
         "//shared/bytesutil:go_default_library",
         "//shared/hashutil:go_default_library",
         "//shared/params:go_default_library",
+        "//shared/testutil:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
+        "@com_github_sirupsen_logrus//hooks/test:go_default_library",
     ],
 )
diff --git a/beacon-chain/attestation/service.go b/beacon-chain/attestation/service.go
index 6994b3946..9bff9e51e 100644
--- a/beacon-chain/attestation/service.go
+++ b/beacon-chain/attestation/service.go
@@ -95,17 +95,12 @@ func (a *Service) IncomingAttestationFeed() *event.Feed {
 //		Attestation` be the attestation with the highest slot number in `store`
 //		from the validator with the given `validator_index`
 func (a *Service) LatestAttestation(ctx context.Context, index uint64) (*pb.Attestation, error) {
-	bState, err := a.beaconDB.HeadState(ctx)
+	validator, err := a.beaconDB.ValidatorFromState(ctx, index)
 	if err != nil {
 		return nil, err
 	}
 
-	// return error if it's an invalid validator index.
-	if index >= uint64(len(bState.ValidatorRegistry)) {
-		return nil, fmt.Errorf("invalid validator index %d", index)
-	}
-
-	pubKey := bytesutil.ToBytes48(bState.ValidatorRegistry[index].Pubkey)
+	pubKey := bytesutil.ToBytes48(validator.Pubkey)
 	a.store.RLock()
 	defer a.store.RUnlock()
 	if _, exists := a.store.m[pubKey]; !exists {
@@ -294,6 +289,15 @@ func (a *Service) updateAttestation(ctx context.Context, headRoot [32]byte, beac
 			continue
 		}
 
+		if i >= len(committee) {
+			log.Errorf("Bitfield points to an invalid index in the committee: bitfield %08b", bitfield)
+			continue
+		}
+
+		if int(committee[i]) >= len(beaconState.ValidatorRegistry) {
+			log.Errorf("Index doesn't exist in validator registry: index %d", committee[i])
+		}
+
 		// If the attestation came from this attester. We use the slot committee to find the
 		// validator's actual index.
 		pubkey := bytesutil.ToBytes48(beaconState.ValidatorRegistry[committee[i]].Pubkey)
diff --git a/beacon-chain/attestation/service_test.go b/beacon-chain/attestation/service_test.go
index 53c53f6ca..a376e4bed 100644
--- a/beacon-chain/attestation/service_test.go
+++ b/beacon-chain/attestation/service_test.go
@@ -14,7 +14,9 @@ import (
 	"github.com/prysmaticlabs/prysm/shared/bytesutil"
 	"github.com/prysmaticlabs/prysm/shared/hashutil"
 	"github.com/prysmaticlabs/prysm/shared/params"
+	"github.com/prysmaticlabs/prysm/shared/testutil"
 	"github.com/sirupsen/logrus"
+	logTest "github.com/sirupsen/logrus/hooks/test"
 )
 
 func init() {
@@ -412,6 +414,49 @@ func TestUpdateLatestAttestation_CacheEnabledAndHit(t *testing.T) {
 	}
 }
 
+func TestUpdateLatestAttestation_InvalidIndex(t *testing.T) {
+	beaconDB := internal.SetupDB(t)
+	hook := logTest.NewGlobal()
+	defer internal.TeardownDB(t, beaconDB)
+	ctx := context.Background()
+
+	var validators []*pb.Validator
+	for i := 0; i < 64; i++ {
+		validators = append(validators, &pb.Validator{
+			Pubkey:          []byte{byte(i)},
+			ActivationEpoch: params.BeaconConfig().GenesisEpoch,
+			ExitEpoch:       params.BeaconConfig().GenesisEpoch + 10,
+		})
+	}
+
+	beaconState := &pb.BeaconState{
+		Slot:              params.BeaconConfig().GenesisSlot + 1,
+		ValidatorRegistry: validators,
+	}
+	block := &pb.BeaconBlock{
+		Slot: params.BeaconConfig().GenesisSlot + 1,
+	}
+	if err := beaconDB.SaveBlock(block); err != nil {
+		t.Fatal(err)
+	}
+	if err := beaconDB.UpdateChainHead(ctx, block, beaconState); err != nil {
+		t.Fatal(err)
+	}
+	service := NewAttestationService(context.Background(), &Config{BeaconDB: beaconDB})
+	attestation := &pb.Attestation{
+		AggregationBitfield: []byte{0xC0},
+		Data: &pb.AttestationData{
+			Slot:  params.BeaconConfig().GenesisSlot + 1,
+			Shard: 1,
+		},
+	}
+
+	if err := service.UpdateLatestAttestation(ctx, attestation); err != nil {
+		t.Fatalf("could not update latest attestation: %v", err)
+	}
+	testutil.AssertLogsContain(t, hook, "Bitfield points to an invalid index in the committee")
+}
+
 func TestUpdateLatestAttestation_BatchUpdate(t *testing.T) {
 	beaconDB := internal.SetupDB(t)
 	defer internal.TeardownDB(t, beaconDB)
diff --git a/beacon-chain/core/state/transition.go b/beacon-chain/core/state/transition.go
index 523d170d3..18145bc3a 100644
--- a/beacon-chain/core/state/transition.go
+++ b/beacon-chain/core/state/transition.go
@@ -376,7 +376,9 @@ func ProcessEpoch(ctx context.Context, state *pb.BeaconState, block *pb.BeaconBl
 		}
 
 	case epochsSinceFinality > 4:
-		log.WithField("epochSinceFinality", epochsSinceFinality).Info("Applying quadratic leak penalties")
+		if config.Logging {
+			log.WithField("epochSinceFinality", epochsSinceFinality).Info("Applying quadratic leak penalties")
+		}
 		// Apply penalties for long inactive FFG source participants.
 		state = bal.InactivityFFGSource(
 			state,