diff --git a/policy/policy.go b/policy/policy.go
index 81a4f34b..dfac8358 100644
--- a/policy/policy.go
+++ b/policy/policy.go
@@ -217,30 +217,30 @@ func (p Policy) Verify(ctx context.Context, opts ...VerifyOption) (bool, map[str
 	resultsByStep := make(map[string]StepResult)
 	for depth := 0; depth < vo.searchDepth; depth++ {
 		for stepName, step := range p.Steps {
-			// Use search to get all the attestations that match the supplied step name and subjects
+			// initialize the result for this step if it hasn't been already
+			if _, ok := resultsByStep[stepName]; !ok {
+				resultsByStep[stepName] = StepResult{Step: stepName}
+			}
+
 			collections, err := vo.verifiedSource.Search(ctx, stepName, vo.subjectDigests, attestationsByStep[stepName])
 			if err != nil {
 				return false, nil, err
 			}
 
 			if len(collections) == 0 {
-				collections = append(collections, source.CollectionVerificationResult{Errors: []error{ErrNoCollections{Step: stepName}}})
+				continue
 			}
 
-			// Verify the functionaries
+			// Verify the functionaries and validate attestations
 			collections = step.checkFunctionaries(collections, trustBundles)
-
 			stepResult := step.validateAttestations(collections)
 
-			// We perform many searches against the same step, so we need to merge the relevant fields
-			if resultsByStep[stepName].Step == "" {
-				resultsByStep[stepName] = stepResult
-			} else {
-				if result, ok := resultsByStep[stepName]; ok {
-					result.Passed = append(result.Passed, stepResult.Passed...)
-					result.Rejected = append(result.Rejected, stepResult.Rejected...)
-					resultsByStep[stepName] = result
-				}
+			// Merge the results
+			if result, ok := resultsByStep[stepName]; ok {
+				result.Passed = append(result.Passed, stepResult.Passed...)
+				result.Rejected = append(result.Rejected, stepResult.Rejected...)
+
+				resultsByStep[stepName] = result
 			}
 
 			for _, coll := range stepResult.Passed {
@@ -303,13 +303,6 @@ func (p Policy) verifyArtifacts(resultsByStep map[string]StepResult) (map[string
 	for _, step := range p.Steps {
 		accepted := false
 		if len(resultsByStep[step.Name].Passed) == 0 {
-			if result, ok := resultsByStep[step.Name]; ok {
-				result.Rejected = append(result.Rejected, RejectedCollection{Reason: fmt.Errorf("failed to verify artifacts for step %s: no passed collections present", step.Name)})
-				resultsByStep[step.Name] = result
-			} else {
-				return nil, fmt.Errorf("failed to find step %s in step results map", step.Name)
-			}
-
 			continue
 		}
 
diff --git a/policy/step.go b/policy/step.go
index 5cd5630d..1dae6fd7 100644
--- a/policy/step.go
+++ b/policy/step.go
@@ -184,7 +184,7 @@ func (s Step) validateAttestations(collectionResults []source.CollectionVerifica
 		if passed {
 			result.Passed = append(result.Passed, collection)
 		} else {
-			r := strings.Join(reasons, ",\n - ")
+			r := strings.Join(reasons, "\n - ")
 			reason := fmt.Sprintf("collection validation failed:\n - %s", r)
 			result.Rejected = append(result.Rejected, RejectedCollection{
 				Collection: collection,
diff --git a/source/memory.go b/source/memory.go
index 8f7450e7..ee40f43e 100644
--- a/source/memory.go
+++ b/source/memory.go
@@ -22,6 +22,7 @@ import (
 	"os"
 
 	"github.com/in-toto/go-witness/dsse"
+	"github.com/in-toto/go-witness/log"
 )
 
 type ErrDuplicateReference string
@@ -31,6 +32,7 @@ func (e ErrDuplicateReference) Error() string {
 }
 
 type MemorySource struct {
+	searched                   bool
 	envelopesByReference       map[string]CollectionEnvelope
 	referencesByCollectionName map[string][]string
 	subjectDigestsByReference  map[string]map[string]struct{}
@@ -39,6 +41,7 @@ type MemorySource struct {
 
 func NewMemorySource() *MemorySource {
 	return &MemorySource{
+		searched:                   false,
 		envelopesByReference:       make(map[string]CollectionEnvelope),
 		referencesByCollectionName: make(map[string][]string),
 		subjectDigestsByReference:  make(map[string]map[string]struct{}),
@@ -104,6 +107,13 @@ func (s *MemorySource) LoadEnvelope(reference string, env dsse.Envelope) error {
 }
 
 func (s *MemorySource) Search(ctx context.Context, collectionName string, subjectDigests, attestations []string) ([]CollectionEnvelope, error) {
+	if s.searched {
+		log.Debug("skipping memory source search: already performed")
+		return []CollectionEnvelope{}, nil
+	} else {
+		s.searched = true
+	}
+
 	matches := make([]CollectionEnvelope, 0)
 	for _, potentialMatchReference := range s.referencesByCollectionName[collectionName] {
 		env, ok := s.envelopesByReference[potentialMatchReference]
@@ -125,20 +135,6 @@ func (s *MemorySource) Search(ctx context.Context, collectionName string, subjec
 			continue
 		}
 
-		// make sure all the expected attestations appear in the collection
-		attestationsMatched := true
-		indexAttestations := s.attestationsByReference[potentialMatchReference]
-		for _, checkAttestation := range attestations {
-			if _, ok := indexAttestations[checkAttestation]; !ok {
-				attestationsMatched = false
-				break
-			}
-		}
-
-		if !attestationsMatched {
-			continue
-		}
-
 		matches = append(matches, env)
 	}