diff --git a/.pending/bugfixes/sdk/4654-validator-slash b/.pending/bugfixes/sdk/4654-validator-slash
new file mode 100644
index 00000000000..c05f19c73de
--- /dev/null
+++ b/.pending/bugfixes/sdk/4654-validator-slash
@@ -0,0 +1 @@
+#4654 validator slash event stored by period and height
\ No newline at end of file
diff --git a/x/distribution/genesis.go b/x/distribution/genesis.go
index 524e2237cae..bd021d66e24 100644
--- a/x/distribution/genesis.go
+++ b/x/distribution/genesis.go
@@ -32,7 +32,7 @@ func InitGenesis(ctx sdk.Context, keeper Keeper, data types.GenesisState) {
 		keeper.SetDelegatorStartingInfo(ctx, del.ValidatorAddress, del.DelegatorAddress, del.StartingInfo)
 	}
 	for _, evt := range data.ValidatorSlashEvents {
-		keeper.SetValidatorSlashEvent(ctx, evt.ValidatorAddress, evt.Height, evt.Event)
+		keeper.SetValidatorSlashEvent(ctx, evt.ValidatorAddress, evt.Height, evt.Period, evt.Event)
 	}
 }
 
@@ -110,6 +110,7 @@ func ExportGenesis(ctx sdk.Context, keeper Keeper) types.GenesisState {
 			slashes = append(slashes, types.ValidatorSlashEventRecord{
 				ValidatorAddress: val,
 				Height:           height,
+				Period:           event.ValidatorPeriod,
 				Event:            event,
 			})
 			return false
diff --git a/x/distribution/keeper/key.go b/x/distribution/keeper/key.go
index c11b9536837..ef367deee76 100644
--- a/x/distribution/keeper/key.go
+++ b/x/distribution/keeper/key.go
@@ -104,10 +104,8 @@ func GetValidatorSlashEventAddressHeight(key []byte) (valAddr sdk.ValAddress, he
 		panic("unexpected key length")
 	}
 	valAddr = sdk.ValAddress(addr)
-	b := key[1+sdk.AddrLen:]
-	if len(b) != 8 {
-		panic("unexpected key length")
-	}
+	startB := 1 + sdk.AddrLen
+	b := key[startB : startB+8] // the next 8 bytes represent the height
 	height = binary.BigEndian.Uint64(b)
 	return
 }
@@ -154,9 +152,23 @@ func GetValidatorSlashEventPrefix(v sdk.ValAddress) []byte {
 	return append(ValidatorSlashEventPrefix, v.Bytes()...)
 }
 
+// gets the prefix key for a validator's slash fraction (ValidatorSlashEventPrefix + height)
+func GetValidatorSlashEventKeyPrefix(v sdk.ValAddress, height uint64) []byte {
+	heightBz := make([]byte, 8)
+	binary.BigEndian.PutUint64(heightBz, height)
+	return append(
+		ValidatorSlashEventPrefix,
+		append(
+			v.Bytes(),
+			heightBz...,
+		)...,
+	)
+}
+
 // gets the key for a validator's slash fraction
-func GetValidatorSlashEventKey(v sdk.ValAddress, height uint64) []byte {
-	b := make([]byte, 8)
-	binary.BigEndian.PutUint64(b, height)
-	return append(append(ValidatorSlashEventPrefix, v.Bytes()...), b...)
+func GetValidatorSlashEventKey(v sdk.ValAddress, height, period uint64) []byte {
+	periodBz := make([]byte, 8)
+	binary.BigEndian.PutUint64(periodBz, period)
+	prefix := GetValidatorSlashEventKeyPrefix(v, height)
+	return append(prefix, periodBz...)
 }
diff --git a/x/distribution/keeper/querier_test.go b/x/distribution/keeper/querier_test.go
index 1709a9cb529..0124bff51ec 100644
--- a/x/distribution/keeper/querier_test.go
+++ b/x/distribution/keeper/querier_test.go
@@ -175,8 +175,8 @@ func TestQueries(t *testing.T) {
 	// test validator slashes query with height range
 	slashOne := types.NewValidatorSlashEvent(3, sdk.NewDecWithPrec(5, 1))
 	slashTwo := types.NewValidatorSlashEvent(7, sdk.NewDecWithPrec(6, 1))
-	keeper.SetValidatorSlashEvent(ctx, valOpAddr1, 3, slashOne)
-	keeper.SetValidatorSlashEvent(ctx, valOpAddr1, 7, slashTwo)
+	keeper.SetValidatorSlashEvent(ctx, valOpAddr1, 3, 0, slashOne)
+	keeper.SetValidatorSlashEvent(ctx, valOpAddr1, 7, 0, slashTwo)
 	slashes := getQueriedValidatorSlashes(t, ctx, cdc, querier, valOpAddr1, 0, 2)
 	require.Equal(t, 0, len(slashes))
 	slashes = getQueriedValidatorSlashes(t, ctx, cdc, querier, valOpAddr1, 0, 5)
diff --git a/x/distribution/keeper/store.go b/x/distribution/keeper/store.go
index 894ef9c568d..6bb766ee34b 100644
--- a/x/distribution/keeper/store.go
+++ b/x/distribution/keeper/store.go
@@ -307,9 +307,9 @@ func (k Keeper) IterateValidatorOutstandingRewards(ctx sdk.Context, handler func
 }
 
 // get slash event for height
-func (k Keeper) GetValidatorSlashEvent(ctx sdk.Context, val sdk.ValAddress, height uint64) (event types.ValidatorSlashEvent, found bool) {
+func (k Keeper) GetValidatorSlashEvent(ctx sdk.Context, val sdk.ValAddress, height, period uint64) (event types.ValidatorSlashEvent, found bool) {
 	store := ctx.KVStore(k.storeKey)
-	b := store.Get(GetValidatorSlashEventKey(val, height))
+	b := store.Get(GetValidatorSlashEventKey(val, height, period))
 	if b == nil {
 		return types.ValidatorSlashEvent{}, false
 	}
@@ -318,10 +318,10 @@ func (k Keeper) GetValidatorSlashEvent(ctx sdk.Context, val sdk.ValAddress, heig
 }
 
 // set slash event for height
-func (k Keeper) SetValidatorSlashEvent(ctx sdk.Context, val sdk.ValAddress, height uint64, event types.ValidatorSlashEvent) {
+func (k Keeper) SetValidatorSlashEvent(ctx sdk.Context, val sdk.ValAddress, height, period uint64, event types.ValidatorSlashEvent) {
 	store := ctx.KVStore(k.storeKey)
 	b := k.cdc.MustMarshalBinaryLengthPrefixed(event)
-	store.Set(GetValidatorSlashEventKey(val, height), b)
+	store.Set(GetValidatorSlashEventKey(val, height, period), b)
 }
 
 // iterate over slash events between heights, inclusive
@@ -329,8 +329,8 @@ func (k Keeper) IterateValidatorSlashEventsBetween(ctx sdk.Context, val sdk.ValA
 	handler func(height uint64, event types.ValidatorSlashEvent) (stop bool)) {
 	store := ctx.KVStore(k.storeKey)
 	iter := store.Iterator(
-		GetValidatorSlashEventKey(val, startingHeight),
-		GetValidatorSlashEventKey(val, endingHeight+1),
+		GetValidatorSlashEventKeyPrefix(val, startingHeight),
+		GetValidatorSlashEventKeyPrefix(val, endingHeight+1),
 	)
 	defer iter.Close()
 	for ; iter.Valid(); iter.Next() {
diff --git a/x/distribution/keeper/validator.go b/x/distribution/keeper/validator.go
index b0bbfca2122..02e29e8367f 100644
--- a/x/distribution/keeper/validator.go
+++ b/x/distribution/keeper/validator.go
@@ -1,6 +1,8 @@
 package keeper
 
 import (
+	"fmt"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
 
 	"github.com/cosmos/cosmos-sdk/x/distribution/types"
@@ -86,33 +88,20 @@ func (k Keeper) decrementReferenceCount(ctx sdk.Context, valAddr sdk.ValAddress,
 }
 
 func (k Keeper) updateValidatorSlashFraction(ctx sdk.Context, valAddr sdk.ValAddress, fraction sdk.Dec) {
-	if fraction.GT(sdk.OneDec()) {
-		panic("fraction greater than one")
+	if fraction.GT(sdk.OneDec()) || fraction.LT(sdk.ZeroDec()) {
+		panic(fmt.Sprintf("fraction must be >=0 and <=1, current fraction: %v", fraction))
 	}
-	height := uint64(ctx.BlockHeight())
-	currentFraction := sdk.ZeroDec()
-	endedPeriod := k.GetValidatorCurrentRewards(ctx, valAddr).Period - 1
-	current, found := k.GetValidatorSlashEvent(ctx, valAddr, height)
-	if found {
-		// there has already been a slash event this height,
-		// and we don't need to store more than one,
-		// so just update the current slash fraction
-		currentFraction = current.Fraction
-	} else {
-		val := k.stakingKeeper.Validator(ctx, valAddr)
-		// increment current period
-		endedPeriod = k.incrementValidatorPeriod(ctx, val)
-		// increment reference count on period we need to track
-		k.incrementReferenceCount(ctx, valAddr, endedPeriod)
-	}
-	currentMultiplicand := sdk.OneDec().Sub(currentFraction)
-	newMultiplicand := sdk.OneDec().Sub(fraction)
 
-	// using MulTruncate here conservatively increases the slashing amount
-	updatedFraction := sdk.OneDec().Sub(currentMultiplicand.MulTruncate(newMultiplicand))
+	val := k.stakingKeeper.Validator(ctx, valAddr)
 
-	if updatedFraction.LT(sdk.ZeroDec()) {
-		panic("negative slash fraction")
-	}
-	k.SetValidatorSlashEvent(ctx, valAddr, height, types.NewValidatorSlashEvent(endedPeriod, updatedFraction))
+	// increment current period
+	newPeriod := k.incrementValidatorPeriod(ctx, val)
+
+	// increment reference count on period we need to track
+	k.incrementReferenceCount(ctx, valAddr, newPeriod)
+
+	slashEvent := types.NewValidatorSlashEvent(newPeriod, fraction)
+	height := uint64(ctx.BlockHeight())
+
+	k.SetValidatorSlashEvent(ctx, valAddr, height, newPeriod, slashEvent)
 }
diff --git a/x/distribution/types/genesis.go b/x/distribution/types/genesis.go
index e87d8a33fde..1e27cff3f1b 100644
--- a/x/distribution/types/genesis.go
+++ b/x/distribution/types/genesis.go
@@ -49,6 +49,7 @@ type DelegatorStartingInfoRecord struct {
 type ValidatorSlashEventRecord struct {
 	ValidatorAddress sdk.ValAddress      `json:"validator_address"`
 	Height           uint64              `json:"height"`
+	Period           uint64              `json:"period"`
 	Event            ValidatorSlashEvent `json:"validator_slash_event"`
 }