diff --git a/src/main/java/org/folio/linked/data/service/rdf/RdfImportServiceImpl.java b/src/main/java/org/folio/linked/data/service/rdf/RdfImportServiceImpl.java
index 6b0085f1..04710822 100644
--- a/src/main/java/org/folio/linked/data/service/rdf/RdfImportServiceImpl.java
+++ b/src/main/java/org/folio/linked/data/service/rdf/RdfImportServiceImpl.java
@@ -68,7 +68,7 @@ private ImportUtils.ImportReport doImport(Set<Resource> resources) {
     var mockResourcesSearchResult = lccnResourceService.findMockResources(resources);
     resources.forEach(resourceModel -> {
       try {
-        resourceModel = lccnResourceService.unMockLccnResource(resourceModel, mockResourcesSearchResult);
+        resourceModel = lccnResourceService.unMockLccnEdges(resourceModel, mockResourcesSearchResult);
         var resource = resourceModelMapper.toEntity(resourceModel);
         metadataService.ensure(resource);
         var saveGraphResult = resourceGraphService.saveMergingGraphInNewTransaction(resource);
diff --git a/src/main/java/org/folio/linked/data/service/search/lccn/LccnResourceService.java b/src/main/java/org/folio/linked/data/service/search/lccn/LccnResourceService.java
index cc28994d..78715757 100644
--- a/src/main/java/org/folio/linked/data/service/search/lccn/LccnResourceService.java
+++ b/src/main/java/org/folio/linked/data/service/search/lccn/LccnResourceService.java
@@ -11,7 +11,7 @@ public interface LccnResourceService {
 
   Map<String, LccnResourceSearchResult> findMockResources(Set<Resource> resources);
 
-  Resource unMockLccnResource(Resource resourceModel, Map<String, LccnResourceSearchResult> searchResults);
+  Resource unMockLccnEdges(Resource resourceModel, Map<String, LccnResourceSearchResult> searchResults);
 
   record LccnResourceSearchResult(@Nullable ResourceSubgraphView subgraphView, @Nonnull String inventoryId) {
   }
diff --git a/src/main/java/org/folio/linked/data/service/search/lccn/LccnResourceServiceImpl.java b/src/main/java/org/folio/linked/data/service/search/lccn/LccnResourceServiceImpl.java
index d29e9e95..fb8e2998 100644
--- a/src/main/java/org/folio/linked/data/service/search/lccn/LccnResourceServiceImpl.java
+++ b/src/main/java/org/folio/linked/data/service/search/lccn/LccnResourceServiceImpl.java
@@ -10,6 +10,7 @@
 import java.util.Collection;
 import java.util.HashSet;
 import java.util.Map;
+import java.util.Optional;
 import java.util.Set;
 import lombok.RequiredArgsConstructor;
 import org.folio.ld.dictionary.model.FolioMetadata;
@@ -26,7 +27,6 @@
 @Service
 @RequiredArgsConstructor
 public class LccnResourceServiceImpl implements LccnResourceService {
-  private static final String NOT_FOUND_MESSAGE = "Resource presented only with LCCN [%s] is not found in %s";
   private final SearchClient searchClient;
   private final MockLccnResourceService mockLccnResourceService;
   private final ResourceSubgraphViewMapper resourceSubgraphViewMapper;
@@ -63,24 +63,20 @@ public Map<String, LccnResourceSearchResult> findMockResources(Set<Resource> res
   }
 
   @Override
-  public Resource unMockLccnResource(Resource resourceModel, Map<String, LccnResourceSearchResult> searchResults) {
-    return mockLccnResourceService.unMockLccnResource(resourceModel, lccn -> getLccnResource(lccn, searchResults));
+  public Resource unMockLccnEdges(Resource resource, Map<String, LccnResourceSearchResult> searchResults) {
+    return mockLccnResourceService.unMockLccnEdges(resource, lccn -> getLccnResource(lccn, searchResults));
   }
 
-  private Resource getLccnResource(String lccn, Map<String, LccnResourceSearchResult> searchResults) {
+  private Optional<Resource> getLccnResource(String lccn, Map<String, LccnResourceSearchResult> searchResults) {
     return ofNullable(searchResults.get(lccn))
-      .map(searchResult -> {
+      .flatMap(searchResult -> {
         var inventoryId = searchResult.inventoryId();
         return ofNullable(searchResult.subgraphView())
           .flatMap(rsw ->
             resourceSubgraphViewMapper.fromJson(rsw.getResourceSubgraph())
               .map(r -> r.setFolioMetadata(new FolioMetadata().setInventoryId(rsw.getInventoryId())))
           )
-          .or(() -> resourceMarcAuthorityService.fetchResourceFromSrsByInventoryId(inventoryId))
-          .orElseThrow(
-            () -> new RuntimeException(NOT_FOUND_MESSAGE.formatted(lccn, "SRS by inventoryId " + inventoryId))
-          );
-      })
-      .orElseThrow(() -> new RuntimeException(NOT_FOUND_MESSAGE.formatted(lccn, "Search")));
+          .or(() -> resourceMarcAuthorityService.fetchResourceFromSrsByInventoryId(inventoryId));
+      });
   }
 }
diff --git a/src/test/java/org/folio/linked/data/service/rdf/RdfImportServiceTest.java b/src/test/java/org/folio/linked/data/service/rdf/RdfImportServiceTest.java
index de2df8ab..cf366057 100644
--- a/src/test/java/org/folio/linked/data/service/rdf/RdfImportServiceTest.java
+++ b/src/test/java/org/folio/linked/data/service/rdf/RdfImportServiceTest.java
@@ -73,7 +73,7 @@ void importFile_createsResources_whenValidFileProvided() throws IOException {
     var searchResults = new HashMap<String, LccnResourceService.LccnResourceSearchResult>();
     when(lccnResourceService.findMockResources(resources)).thenReturn(searchResults);
     var unMockedResource = new Resource().setId(1L);
-    when(lccnResourceService.unMockLccnResource(any(), any())).thenReturn(unMockedResource);
+    when(lccnResourceService.unMockLccnEdges(any(), any())).thenReturn(unMockedResource);
     when(resourceModelMapper.toEntity(unMockedResource)).thenReturn(entity);
     var saveGraphResult = new SaveGraphResult(entity, Set.of(entity), Set.of());
     when(resourceGraphService.saveMergingGraphInNewTransaction(entity)).thenReturn(saveGraphResult);
@@ -98,7 +98,7 @@ void importFile_updatesResources_whenValidFileProvidedAndResourceExists() throws
     var searchResults = new HashMap<String, LccnResourceService.LccnResourceSearchResult>();
     when(lccnResourceService.findMockResources(resources)).thenReturn(searchResults);
     var unMockedResource = new Resource().setId(1L);
-    when(lccnResourceService.unMockLccnResource(any(), any())).thenReturn(unMockedResource);
+    when(lccnResourceService.unMockLccnEdges(any(), any())).thenReturn(unMockedResource);
     when(resourceModelMapper.toEntity(unMockedResource)).thenReturn(entity);
     var saveGraphResult = new SaveGraphResult(entity, Set.of(), Set.of(entity));
     when(resourceGraphService.saveMergingGraphInNewTransaction(entity)).thenReturn(saveGraphResult);
@@ -183,7 +183,7 @@ void saveImportEventResources_shouldSaveResources() {
     var expectedImportEventResult = new ImportEventResult().setEventTs(Long.parseLong(ts));
     when(importEventResultMapper.fromImportReport(eq(event), any(), any()))
       .thenReturn(expectedImportEventResult);
-    when(lccnResourceService.unMockLccnResource(any(), any()))
+    when(lccnResourceService.unMockLccnEdges(any(), any()))
       .thenAnswer(inv -> inv.getArgument(0));
 
 
diff --git a/src/test/java/org/folio/linked/data/service/search/lccn/LccnResourceServiceTest.java b/src/test/java/org/folio/linked/data/service/search/lccn/LccnResourceServiceTest.java
index e391b963..f588818f 100644
--- a/src/test/java/org/folio/linked/data/service/search/lccn/LccnResourceServiceTest.java
+++ b/src/test/java/org/folio/linked/data/service/search/lccn/LccnResourceServiceTest.java
@@ -2,7 +2,6 @@
 
 import static java.util.Optional.empty;
 import static java.util.Optional.of;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;
 import static org.folio.linked.data.service.search.lccn.LccnResourceService.LccnResourceSearchResult;
 import static org.folio.linked.data.test.TestUtil.getLccnResourceSearchResult;
@@ -15,6 +14,7 @@
 import java.util.HashSet;
 import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 import java.util.UUID;
 import java.util.function.Function;
@@ -53,7 +53,7 @@ class LccnResourceServiceTest {
   private ResourceMarcAuthorityService resourceMarcAuthorityService;
 
   @Test
-  void shouldReturnResultsWithFoundResourceAndInventoryId() {
+  void findMockResources_shouldReturnResultsWithFoundResourceAndInventoryId() {
     // given
     var lccn1 = "lccnOfExistedResource";
     var lccn2 = "lccnOfNotExistedResourceButFoundInventoryId";
@@ -85,7 +85,7 @@ void shouldReturnResultsWithFoundResourceAndInventoryId() {
   }
 
   @Test
-  void shouldReturnNothing_ifNoGivenResources() {
+  void findMockResources_shouldReturnNothing_ifNoGivenResources() {
 
     // when
     var result = lccnResourceSearchService.findMockResources(new HashSet<>());
@@ -95,7 +95,7 @@ void shouldReturnNothing_ifNoGivenResources() {
   }
 
   @Test
-  void shouldReturnNothing_ifNoMockLccnResources() {
+  void findMockResources_shouldReturnNothing_ifNoMockLccnResources() {
     // given
     var resources = Set.of(new Resource().setId(1L));
     var lccns = Set.of();
@@ -109,7 +109,7 @@ void shouldReturnNothing_ifNoMockLccnResources() {
   }
 
   @Test
-  void unMockLccnResource_shouldReturnMappedResourceFromSearchResults_ifPresentedInGraph() {
+  void unMockLccnEdges_shouldMapEdgesFromSearchResults_ifPresentedInGraph() {
     // given
     var lccn = UUID.randomUUID().toString();
     var searchResults = new HashMap<String, LccnResourceSearchResult>();
@@ -119,20 +119,18 @@ void unMockLccnResource_shouldReturnMappedResourceFromSearchResults_ifPresentedI
     var resource = new org.folio.ld.dictionary.model.Resource().setId(1L);
     doReturn(of(resource)).when(resourceSubgraphViewMapper).fromJson("1");
     var mockResource = new Resource().setId(2L);
-    when(mockLccnResourceService.unMockLccnResource(any(), any())).thenAnswer(inv -> {
-      var lccnProvider = (Function<String, Resource>) inv.getArgument(1);
-      return lccnProvider.apply(lccn);
-    });
+    when(mockLccnResourceService.unMockLccnEdges(any(), any()))
+      .thenAnswer(inv -> ((Function<String, Optional<Resource>>) inv.getArgument(1)).apply(lccn).get());
 
     // when
-    var result = lccnResourceSearchService.unMockLccnResource(mockResource, searchResults);
+    var result = lccnResourceSearchService.unMockLccnEdges(mockResource, searchResults);
 
     // then
     assertThat(result).isEqualTo(resource);
   }
 
   @Test
-  void unMockLccnResource_shouldReturnResourceFromResourceMarcAuthorityService_ifNotPresentedInGraph() {
+  void unMockLccnResource_shouldMapEdgesTakenFromMarcAuthorityService_ifNotPresentedInGraph() {
     // given
     var lccn = UUID.randomUUID().toString();
     var searchResults = new HashMap<String, LccnResourceSearchResult>();
@@ -143,20 +141,18 @@ void unMockLccnResource_shouldReturnResourceFromResourceMarcAuthorityService_ifN
     var resource = new org.folio.ld.dictionary.model.Resource().setId(1L);
     doReturn(of(resource)).when(resourceMarcAuthorityService).fetchResourceFromSrsByInventoryId(inventoryId);
     var mockResource = new Resource().setId(2L);
-    when(mockLccnResourceService.unMockLccnResource(any(), any())).thenAnswer(inv -> {
-      var lccnProvider = (Function<String, Resource>) inv.getArgument(1);
-      return lccnProvider.apply(lccn);
-    });
+    when(mockLccnResourceService.unMockLccnEdges(any(), any()))
+      .thenAnswer(inv -> ((Function<String, Optional<Resource>>) inv.getArgument(1)).apply(lccn).get());
 
     // when
-    var result = lccnResourceSearchService.unMockLccnResource(mockResource, searchResults);
+    var result = lccnResourceSearchService.unMockLccnEdges(mockResource, searchResults);
 
     // then
     assertThat(result).isEqualTo(resource);
   }
 
   @Test
-  void unMockLccnResource_shouldThrowException_ifResourceNotFoundByResourceMarcAuthorityService() {
+  void unMockLccnResource_shouldNotMapAnything_ifNotFoundInMarcAuthorityService() {
     // given
     var lccn = UUID.randomUUID().toString();
     var searchResults = new HashMap<String, LccnResourceSearchResult>();
@@ -166,36 +162,31 @@ void unMockLccnResource_shouldThrowException_ifResourceNotFoundByResourceMarcAut
     searchResults.put(lccn + "3", getLccnResourceSearchResult("3", null));
     doReturn(empty()).when(resourceMarcAuthorityService).fetchResourceFromSrsByInventoryId(inventoryId);
     var mockResource = new Resource().setId(2L);
-    when(mockLccnResourceService.unMockLccnResource(any(), any())).thenAnswer(inv -> {
-      var lccnProvider = (Function<String, Resource>) inv.getArgument(1);
-      return lccnProvider.apply(lccn);
-    });
+    when(mockLccnResourceService.unMockLccnEdges(any(), any()))
+      .thenAnswer(inv -> ((Function<String, Optional<Resource>>) inv.getArgument(1)).apply(lccn).orElse(null));
 
     // when
-    var result = assertThatThrownBy(() -> lccnResourceSearchService.unMockLccnResource(mockResource, searchResults));
+    var result = lccnResourceSearchService.unMockLccnEdges(mockResource, searchResults);
 
     // then
-    result.hasMessage("Resource presented only with LCCN [" + lccn
-      + "] is not found in SRS by inventoryId " + inventoryId);
+    assertThat(result).isNull();
   }
 
   @Test
-  void unMockLccnResource_shouldThrowException_ifResourceNotFoundBySearch() {
+  void unMockLccnResource_shouldNotMapAnything_ifEdgesNotFoundBySearch() {
     // given
     var lccn = UUID.randomUUID().toString();
     var searchResults = new HashMap<String, LccnResourceSearchResult>();
     searchResults.put(lccn + "2", getLccnResourceSearchResult("2", null));
     searchResults.put(lccn + "3", getLccnResourceSearchResult("3", null));
     var mockResource = new Resource().setId(2L);
-    when(mockLccnResourceService.unMockLccnResource(any(), any())).thenAnswer(inv -> {
-      var lccnProvider = (Function<String, Resource>) inv.getArgument(1);
-      return lccnProvider.apply(lccn);
-    });
+    when(mockLccnResourceService.unMockLccnEdges(any(), any()))
+      .thenAnswer(inv -> ((Function<String, Optional<Resource>>) inv.getArgument(1)).apply(lccn).orElse(null));
 
     // when
-    var result = assertThatThrownBy(() -> lccnResourceSearchService.unMockLccnResource(mockResource, searchResults));
+    var result = lccnResourceSearchService.unMockLccnEdges(mockResource, searchResults);
 
     // then
-    result.hasMessage("Resource presented only with LCCN [" + lccn + "] is not found in Search");
+    assertThat(result).isNull();
   }
 }