diff --git a/.env.example b/.env.example
index c6015e9..cacd6a1 100644
--- a/.env.example
+++ b/.env.example
@@ -2,9 +2,10 @@
 DEBUG=True
 APP_ENV=development
 
-# Search Engine
+# Search Engine, Supported values: tavily (recommended), duckduckgo, brave_search, arxiv
 SEARCH_API=tavily
 TAVILY_API_KEY=tvly-xxx
+# BRAVE_SEARCH_API_KEY=xxx # Required only if SEARCH_API is brave_search
 # JINA_API_KEY=jina_xxx # Optional, default is None
 
 # Optional, volcengine TTS for generating podcast
diff --git a/src/graph/nodes.py b/src/graph/nodes.py
index a87bf56..b0b8cad 100644
--- a/src/graph/nodes.py
+++ b/src/graph/nodes.py
@@ -28,7 +28,7 @@ from src.prompts.template import apply_prompt_template
 from src.utils.json_utils import repair_json_output
 
 from .types import State
-from ..config import SEARCH_MAX_RESULTS
+from ..config import SEARCH_MAX_RESULTS, SELECTED_SEARCH_ENGINE, SearchEngine
 
 logger = logging.getLogger(__name__)
 
@@ -45,19 +45,24 @@ def handoff_to_planner(
 
 
 def background_investigation_node(state: State) -> Command[Literal["planner"]]:
-
     logger.info("background investigation node is running.")
-    searched_content = LoggedTavilySearch(max_results=SEARCH_MAX_RESULTS).invoke(
-        {"query": state["messages"][-1].content}
-    )
-    background_investigation_results = None
-    if isinstance(searched_content, list):
-        background_investigation_results = [
-            {"title": elem["title"], "content": elem["content"]}
-            for elem in searched_content
-        ]
+    query = state["messages"][-1].content
+    if SELECTED_SEARCH_ENGINE == SearchEngine.TAVILY:
+        searched_content = LoggedTavilySearch(max_results=SEARCH_MAX_RESULTS).invoke(
+            {"query": query}
+        )
+        background_investigation_results = None
+        if isinstance(searched_content, list):
+            background_investigation_results = [
+                {"title": elem["title"], "content": elem["content"]}
+                for elem in searched_content
+            ]
+        else:
+            logger.error(
+                f"Tavily search returned malformed response: {searched_content}"
+            )
     else:
-        logger.error(f"Tavily search returned malformed response: {searched_content}")
+        background_investigation_results = web_search_tool.invoke(query)
     return Command(
         update={
             "background_investigation_results": json.dumps(
diff --git a/src/tools/search.py b/src/tools/search.py
index caa70a0..e4c92ad 100644
--- a/src/tools/search.py
+++ b/src/tools/search.py
@@ -14,11 +14,10 @@ from src.tools.tavily_search.tavily_search_results_with_images import (
     TavilySearchResultsWithImages,
 )
 
-from .decorators import create_logged_tool
+from src.tools.decorators import create_logged_tool
 
 logger = logging.getLogger(__name__)
 
-
 LoggedTavilySearch = create_logged_tool(TavilySearchResultsWithImages)
 tavily_search_tool = LoggedTavilySearch(
     name="web_search",
@@ -53,5 +52,7 @@ arxiv_search_tool = LoggedArxivSearch(
 )
 
 if __name__ == "__main__":
-    results = tavily_search_tool.invoke("cute panda")
+    results = LoggedDuckDuckGoSearch(
+        name="web_search", max_results=SEARCH_MAX_RESULTS, output_format="list"
+    ).invoke("cute panda")
     print(json.dumps(results, indent=2, ensure_ascii=False))