diff --git a/OpenSim/Region/Framework/Scenes/SceneGraph.cs b/OpenSim/Region/Framework/Scenes/SceneGraph.cs
index 66fb493551..dd0ca43e67 100644
--- a/OpenSim/Region/Framework/Scenes/SceneGraph.cs
+++ b/OpenSim/Region/Framework/Scenes/SceneGraph.cs
@@ -215,27 +215,13 @@ namespace OpenSim.Region.Framework.Scenes
                 if (sp.IsChildAgent)
                     continue;
 
-                if (sp.ParentID != 0)
-                {
-                    // sitting avatar
-                    SceneObjectPart sop = m_parentScene.GetSceneObjectPart(sp.ParentID);
-                    if (sop != null)
-                    {
-                        coarseLocations.Add(sop.AbsolutePosition + sp.OffsetPosition);
-                        avatarUUIDs.Add(sp.UUID);
-                    }
-                    else
-                    {
-                        // we can't find the parent..  ! arg!
-                        coarseLocations.Add(sp.AbsolutePosition);
-                        avatarUUIDs.Add(sp.UUID);
-                    }
-                }
+                SceneObjectPart sitPart = sp.ParentPart;
+                if (sitPart != null)
+                    coarseLocations.Add(sitPart.AbsolutePosition + sp.OffsetPosition);
                 else
-                {
                     coarseLocations.Add(sp.AbsolutePosition);
-                    avatarUUIDs.Add(sp.UUID);
-                }
+
+                avatarUUIDs.Add(sp.UUID);
             }
         }
 
diff --git a/OpenSim/Region/Framework/Scenes/ScenePresence.cs b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
index c9dc7fd71e..aab0bf0a48 100644
--- a/OpenSim/Region/Framework/Scenes/ScenePresence.cs
+++ b/OpenSim/Region/Framework/Scenes/ScenePresence.cs
@@ -432,7 +432,7 @@ namespace OpenSim.Region.Framework.Scenes
         {
             get
             {
-                if (PhysicsActor != null && m_parentID == 0)
+                if (PhysicsActor != null && ParentID == 0)
                 {
                     m_pos = PhysicsActor.Position;
 
@@ -504,6 +504,7 @@ namespace OpenSim.Region.Framework.Scenes
                 // There is no offset position when not seated
                 if (ParentID == 0)
                     return;
+
                 m_pos = value;
             }
         }
@@ -562,19 +563,18 @@ namespace OpenSim.Region.Framework.Scenes
 
         public bool IsChildAgent { get; set; }
 
-        public uint ParentID
-        {
-            get { return m_parentID; }
-            set { m_parentID = value; }
-        }
-        private uint m_parentID;
+        /// <summary>
+        /// If the avatar is sitting, the local ID of the prim that it's sitting on.  If not sitting then zero.
+        /// </summary>
+        public uint ParentID { get; set; }
 
-        public SceneObjectPart ParentPart
-        {
-            get { return m_parentPart; }
-            set { m_parentPart = value; }
-        }
-        private SceneObjectPart m_parentPart = null;
+        /// <summary>
+        /// If the avatar is sitting, the prim that it's sitting on.  If not sitting then null.
+        /// </summary>
+        /// <remarks>
+        /// If you use this property then you must take a reference since another thread could set it to null.
+        /// </remarks>
+        public SceneObjectPart ParentPart { get; set; }
 
         public float Health
         {
diff --git a/OpenSim/Region/RegionCombinerModule/RegionCombinerModule.cs b/OpenSim/Region/RegionCombinerModule/RegionCombinerModule.cs
index 09da97a527..a2e3ac2c44 100644
--- a/OpenSim/Region/RegionCombinerModule/RegionCombinerModule.cs
+++ b/OpenSim/Region/RegionCombinerModule/RegionCombinerModule.cs
@@ -716,29 +716,17 @@ namespace OpenSim.Region.RegionCombinerModule
             {
                 if (sp.UUID != presence.UUID)
                 {
-                    if (sp.ParentID != 0)
-                    {
-                        // sitting avatar
-                        SceneObjectPart sop = connectiondata.RegionScene.GetSceneObjectPart(sp.ParentID);
-                        if (sop != null)
-                        {
-                            CoarseLocations.Add(sop.AbsolutePosition + sp.AbsolutePosition);
-                            AvatarUUIDs.Add(sp.UUID);
-                        }
-                        else
-                        {
-                            // we can't find the parent..  ! arg!
-                            CoarseLocations.Add(sp.AbsolutePosition);
-                            AvatarUUIDs.Add(sp.UUID);
-                        }
-                    }
+                    SceneObjectPart sitPart = sp.ParentPart;
+
+                    if (sitPart != null)
+                        CoarseLocations.Add(sitPart.AbsolutePosition + sp.AbsolutePosition);
                     else
-                    {
                         CoarseLocations.Add(sp.AbsolutePosition);
-                        AvatarUUIDs.Add(sp.UUID);
-                    }
+
+                    AvatarUUIDs.Add(sp.UUID);
                 }
             });
+
             DistributeCourseLocationUpdates(CoarseLocations, AvatarUUIDs, connectiondata, presence);
         }
 
diff --git a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
index 786ae6e6ff..bb374ed002 100644
--- a/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
+++ b/OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs
@@ -3825,7 +3825,8 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
             List<String> nametable = new List<String>();
             World.ForEachRootScenePresence(delegate(ScenePresence presence)
             {
-                if (presence.ParentID != 0 && m_host.ParentGroup.HasChildPrim(presence.ParentID))
+                SceneObjectPart sitPart = presence.ParentPart;
+                if (sitPart != null && m_host.ParentGroup.HasChildPrim(sitPart.LocalId))
                     nametable.Add(presence.ControllingClient.Name);
             });
 
@@ -4393,22 +4394,11 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
 
                 // Find pushee position
                 // Pushee Linked?
-                if (pusheeav.ParentID != 0)
-                {
-                    SceneObjectPart parentobj = World.GetSceneObjectPart(pusheeav.ParentID);
-                    if (parentobj != null)
-                    {
-                        PusheePos = parentobj.AbsolutePosition;
-                    }
-                    else
-                    {
-                        PusheePos = pusheeav.AbsolutePosition;
-                    }
-                }
+                SceneObjectPart sitPart = pusheeav.ParentPart;
+                if (sitPart != null)
+                    PusheePos = sitPart.AbsolutePosition;
                 else
-                {
                     PusheePos = pusheeav.AbsolutePosition;
-                }
             }
 
             if (!pusheeIsAvatar)
@@ -5603,7 +5593,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
                     flags |= ScriptBaseClass.AGENT_IN_AIR;
             }
 
-             if (agent.ParentID != 0)
+             if (agent.ParentPart != null)
              {
                  flags |= ScriptBaseClass.AGENT_ON_OBJECT;
                  flags |= ScriptBaseClass.AGENT_SITTING;
@@ -7692,7 +7682,7 @@ namespace OpenSim.Region.ScriptEngine.Shared.Api
             World.ForEachRootScenePresence(delegate(ScenePresence presence)
             {
                 if (presence.ParentID != 0 && m_host.ParentGroup.HasChildPrim(presence.ParentID))
-                        avatarCount++;
+                    avatarCount++;
             });
 
             return m_host.ParentGroup.PrimCount + avatarCount;