diff --git a/verification/src/accept_chain.rs b/verification/src/accept_chain.rs
index a70c617f..579647da 100644
--- a/verification/src/accept_chain.rs
+++ b/verification/src/accept_chain.rs
@@ -16,6 +16,7 @@ pub struct ChainAcceptor<'a> {
 
 impl<'a> ChainAcceptor<'a> {
 	pub fn new(store: &'a SharedStore, network: Magic, block: CanonBlock<'a>, height: u32) -> Self {
+		trace!(target: "verification", "Block verification {}", block.hash().to_reversed_str());
 		let prevouts = DuplexTransactionOutputProvider::new(store.as_previous_transaction_output_provider(), block.raw());
 		ChainAcceptor {
 			block: BlockAcceptor::new(store.as_previous_transaction_output_provider(), network, block, height),
diff --git a/verification/src/accept_transaction.rs b/verification/src/accept_transaction.rs
index fa5a6eab..ef222e1c 100644
--- a/verification/src/accept_transaction.rs
+++ b/verification/src/accept_transaction.rs
@@ -32,6 +32,7 @@ impl<'a> TransactionAcceptor<'a> {
 		height: u32,
 		time: u32,
 	) -> Self {
+		trace!(target: "verification", "Tx verification {}", transaction.hash.to_reversed_str());
 		let params = network.consensus_params();
 		TransactionAcceptor {
 			bip30: TransactionBip30::new_for_sync(transaction, meta_store, params.clone(), block_hash, height),
@@ -91,6 +92,7 @@ impl<'a> MemoryPoolTransactionAcceptor<'a> {
 		height: u32,
 		time: u32,
 	) -> Self {
+		trace!(target: "verification", "Mempool-Tx verification {}", transaction.hash.to_reversed_str());
 		let params = network.consensus_params();
 		MemoryPoolTransactionAcceptor {
 			bip30: TransactionBip30::new_for_mempool(transaction, meta_store),
@@ -378,17 +380,14 @@ impl<'a> TransactionDoubleSpend<'a> {
 
 impl<'a> TransactionRule for TransactionDoubleSpend<'a> {
 	fn check(&self) -> Result<(), TransactionError> {
-		let double_spent_input = self.transaction.raw.inputs.iter()
-			.find(|input| self.store.is_spent(&input.previous_output).unwrap_or(false));
-
-		match double_spent_input {
-			Some(input) => {
-				Err(TransactionError::UsingSpentOutput(
+		for input in &self.transaction.raw.inputs {
+			if self.store.is_spent(&input.previous_output).unwrap_or(false) {
+				return Err(TransactionError::UsingSpentOutput(
 					input.previous_output.hash.clone(),
 					input.previous_output.index
 				))
-			},
-			None => Ok(())
+			}
 		}
+		Ok(())
 	}
 }
diff --git a/verification/src/verify_chain.rs b/verification/src/verify_chain.rs
index e8e3d1cd..84c663cd 100644
--- a/verification/src/verify_chain.rs
+++ b/verification/src/verify_chain.rs
@@ -14,6 +14,7 @@ pub struct ChainVerifier<'a> {
 
 impl<'a> ChainVerifier<'a> {
 	pub fn new(block: &'a IndexedBlock, network: Magic, current_time: u32) -> Self {
+		trace!(target: "verification", "Block pre-verification {}", block.hash().to_reversed_str());
 		ChainVerifier {
 			block: BlockVerifier::new(block),
 			header: HeaderVerifier::new(&block.header, network, current_time),
diff --git a/verification/src/verify_transaction.rs b/verification/src/verify_transaction.rs
index c09abdec..b6f2a9c0 100644
--- a/verification/src/verify_transaction.rs
+++ b/verification/src/verify_transaction.rs
@@ -13,6 +13,7 @@ pub struct TransactionVerifier<'a> {
 
 impl<'a> TransactionVerifier<'a> {
 	pub fn new(transaction: &'a IndexedTransaction) -> Self {
+		trace!(target: "verification", "Tx pre-verification {}", transaction.hash.to_reversed_str());
 		TransactionVerifier {
 			empty: TransactionEmpty::new(transaction),
 			null_non_coinbase: TransactionNullNonCoinbase::new(transaction),
@@ -38,6 +39,7 @@ pub struct MemoryPoolTransactionVerifier<'a> {
 
 impl<'a> MemoryPoolTransactionVerifier<'a> {
 	pub fn new(transaction: &'a IndexedTransaction) -> Self {
+		trace!(target: "verification", "Mempool-Tx pre-verification {}", transaction.hash.to_reversed_str());
 		MemoryPoolTransactionVerifier {
 			empty: TransactionEmpty::new(transaction),
 			null_non_coinbase: TransactionNullNonCoinbase::new(transaction),