diff --git a/pisa/db_manager.py b/pisa/db_manager.py
index 339140d..cd6428f 100644
--- a/pisa/db_manager.py
+++ b/pisa/db_manager.py
@@ -9,6 +9,9 @@ logger = Logger("DBManager")
 
 class DBManager:
     def __init__(self, db_path):
+        if not isinstance(db_path, str):
+            raise ValueError("db_path must be a valid path/name")
+
         try:
             self.db = plyvel.DB(db_path)
 
@@ -22,13 +25,13 @@ class DBManager:
 
         for k, v in self.db.iterator(prefix=prefix.encode('utf-8')):
             # Get uuid and appointment_data from the db
-            uuid = k[1:].decode('utf-8')
+            uuid = k[len(prefix):].decode('utf-8')
             data[uuid] = json.loads(v)
 
         return data
 
-    def get_last_known_block(self, prefix):
-        last_block = self.db.get(prefix)
+    def get_last_known_block(self, key):
+        last_block = self.db.get(key.encode('utf-8'))
 
         if last_block:
             last_block = last_block.decode('utf-8')
@@ -74,8 +77,14 @@ class DBManager:
         self.delete_entry(uuid, prefix=RESPONDER_PREFIX)
         logger.info("Deleting appointment from Responder's db", uuid=uuid)
 
-    def store_last_block_watcher(self, block_hash):
+    def load_last_block_hash_watcher(self):
+        return self.get_last_known_block(WATCHER_LAST_BLOCK_KEY)
+
+    def load_last_block_hash_responder(self):
+        return self.get_last_known_block(RESPONDER_LAST_BLOCK_KEY)
+
+    def store_last_block_hash_watcher(self, block_hash):
         self.create_entry(WATCHER_LAST_BLOCK_KEY, block_hash)
 
-    def store_last_block_responder(self, block_hash):
+    def store_last_block_hash_responder(self, block_hash):
         self.create_entry(RESPONDER_LAST_BLOCK_KEY, block_hash)
diff --git a/pisa/responder.py b/pisa/responder.py
index 36c1295..e92a4eb 100644
--- a/pisa/responder.py
+++ b/pisa/responder.py
@@ -165,7 +165,7 @@ class Responder:
                     self.handle_reorgs()
 
                 # Register the last processed block for the responder
-                self.db_manager.store_last_block_responder(block_hash)
+                self.db_manager.store_last_block_hash_responder(block_hash)
 
                 prev_block_hash = block.get('hash')
 
diff --git a/pisa/watcher.py b/pisa/watcher.py
index 944d0c9..2017e58 100644
--- a/pisa/watcher.py
+++ b/pisa/watcher.py
@@ -141,7 +141,7 @@ class Watcher:
                     self.db_manager.store_watcher_appointment(uuid, appointment.to_json())
 
                     # Register the last processed block for the watcher
-                    self.db_manager.store_last_block_watcher(block_hash)
+                    self.db_manager.store_last_block_hash_watcher(block_hash)
 
         # Go back to sleep if there are no more appointments
         self.asleep = True