diff --git a/letta/server/server.py b/letta/server/server.py
index d9036f26a0..5088e9effc 100644
--- a/letta/server/server.py
+++ b/letta/server/server.py
@@ -1623,6 +1623,11 @@ def detach_source_from_agent(
         agent = self._get_or_load_agent(agent_id=agent_id)
         archival_memory = agent.persistence_manager.archival_memory
         archival_memory.storage.delete({"source_id": source_id})
+
+        # delete agent-source mapping
+        self.ms.detach_source(agent_id=agent_id, source_id=source_id)
+
+        # return back source data
         return source
 
     def list_attached_sources(self, agent_id: str) -> List[Source]:
diff --git a/tests/test_client.py b/tests/test_client.py
index b81a0acd51..58c7775ec6 100644
--- a/tests/test_client.py
+++ b/tests/test_client.py
@@ -395,10 +395,12 @@ def test_sources(client: Union[LocalClient, RESTClient], agent: AgentState):
     print(sources)
 
     # detach the source
+    assert len(client.get_archival_memory(agent_id=agent.id)) > 0, "No archival memory"
     deleted_source = client.detach_source(source_id=source.id, agent_id=agent.id)
     assert deleted_source.id == source.id
     archival_memories = client.get_archival_memory(agent_id=agent.id)
     assert len(archival_memories) == 0, f"Failed to detach source: {len(archival_memories)}"
+    assert source.id not in [s.id for s in client.list_attached_sources(agent.id)]
 
     # delete the source
     client.delete_source(source.id)