diff --git a/bloom/merkleblock.go b/bloom/merkleblock.go
index af99db0..1754b0b 100644
--- a/bloom/merkleblock.go
+++ b/bloom/merkleblock.go
@@ -77,8 +77,8 @@ func (m *merkleBlock) traverseAndBuild(height, pos uint32) {
 }
 
 // NewMerkleBlock returns a new *wire.MsgMerkleBlock and an array of the matched
-// transaction hashes based on the passed block and filter.
-func NewMerkleBlock(block *btcutil.Block, filter *Filter) (*wire.MsgMerkleBlock, []*wire.ShaHash) {
+// transaction index numbers based on the passed block and filter.
+func NewMerkleBlock(block *btcutil.Block, filter *Filter) (*wire.MsgMerkleBlock, []uint32) {
 	numTx := uint32(len(block.Transactions()))
 	mBlock := merkleBlock{
 		numTx:       numTx,
@@ -87,11 +87,11 @@ func NewMerkleBlock(block *btcutil.Block, filter *Filter) (*wire.MsgMerkleBlock,
 	}
 
 	// Find and keep track of any transactions that match the filter.
-	var matchedHashes []*wire.ShaHash
-	for _, tx := range block.Transactions() {
+	var matchedIndices []uint32
+	for txIndex, tx := range block.Transactions() {
 		if filter.MatchTxAndUpdate(tx) {
 			mBlock.matchedBits = append(mBlock.matchedBits, 0x01)
-			matchedHashes = append(matchedHashes, tx.Sha())
+			matchedIndices = append(matchedIndices, uint32(txIndex))
 		} else {
 			mBlock.matchedBits = append(mBlock.matchedBits, 0x00)
 		}
@@ -120,5 +120,5 @@ func NewMerkleBlock(block *btcutil.Block, filter *Filter) (*wire.MsgMerkleBlock,
 	for i := uint32(0); i < uint32(len(mBlock.bits)); i++ {
 		msgMerkleBlock.Flags[i/8] |= mBlock.bits[i] << (i % 8)
 	}
-	return &msgMerkleBlock, matchedHashes
+	return &msgMerkleBlock, matchedIndices
 }