diff --git a/src/DotRecast.Detour/DtNavMeshQuery.cs b/src/DotRecast.Detour/DtNavMeshQuery.cs
index 1dce91b..4e9cf18 100644
--- a/src/DotRecast.Detour/DtNavMeshQuery.cs
+++ b/src/DotRecast.Detour/DtNavMeshQuery.cs
@@ -2808,7 +2808,8 @@ namespace DotRecast.Detour
         {
             // Validate input
             if (!m_nav.IsValidPolyRef(startRef) || !RcVec3f.IsFinite(centerPos) || radius < 0
-                || !float.IsFinite(radius) || null == filter)
+                || !float.IsFinite(radius) || null == filter
+                || null == resultRef || null == resultParent)
             {
                 return DtStatus.DT_FAILURE | DtStatus.DT_INVALID_PARAM;
             }
diff --git a/src/DotRecast.Recast.Demo/Tools/TestNavmeshTool.cs b/src/DotRecast.Recast.Demo/Tools/TestNavmeshTool.cs
index 3ee0d28..15370dd 100644
--- a/src/DotRecast.Recast.Demo/Tools/TestNavmeshTool.cs
+++ b/src/DotRecast.Recast.Demo/Tools/TestNavmeshTool.cs
@@ -335,7 +335,14 @@ public class TestNavmeshTool : IRcTool
             if (m_sposSet && m_startRef != 0)
             {
                 m_neighbourhoodRadius = _impl.GetSample().GetSettings().agentRadius * 20.0f;
-                m_navQuery.FindLocalNeighbourhood(m_startRef, m_spos, m_neighbourhoodRadius, m_filter, ref m_polys, ref m_parent);
+                List<long> resultRef = new();
+                List<long> resultParent = new();
+                var status = m_navQuery.FindLocalNeighbourhood(m_startRef, m_spos, m_neighbourhoodRadius, m_filter, ref resultRef, ref resultParent);
+                if (status.Succeeded())
+                {
+                    m_polys = resultRef;
+                    m_parent = resultParent;
+                }
             }
         }
         else if (option.mode == TestNavmeshToolMode.RANDOM_POINTS_IN_CIRCLE)