diff --git a/cpp/BayesTree-inl.h b/cpp/BayesTree-inl.h
index 8ba80c07c..b0581fe73 100644
--- a/cpp/BayesTree-inl.h
+++ b/cpp/BayesTree-inl.h
@@ -78,7 +78,7 @@ namespace gtsam {
 	{
 		node_ptr new_clique(new Node(conditional));
 		nodes_.insert(make_pair(conditional->key(), new_clique));
-	if (parent_clique!=NULL) {
+		if (parent_clique!=NULL) {
 			new_clique->parent_ = parent_clique;
 			parent_clique->children_.push_back(new_clique);
 		}
@@ -102,10 +102,7 @@ namespace gtsam {
 
 		// otherwise, find the parent clique
 		string parent = parents.front();
-		typename Nodes::const_iterator it = nodes_.find(parent);
-		if (it == nodes_.end()) throw(invalid_argument(
-				"BayesTree::insert('"+key+"'): parent '" + parent + "' not yet inserted"));
-		node_ptr parent_clique = it->second;
+		node_ptr parent_clique = (*this)[parent];
 
 		// if the parents and parent clique have the same size, add to parent clique
 		if (parent_clique->size() == parents.size()) {
@@ -130,13 +127,8 @@ namespace gtsam {
 	template<class Factor>
 	boost::shared_ptr<Conditional> BayesTree<Conditional>::marginal(const string& key) const {
 
-		// find the clique to which key belongs
-		typename Nodes::const_iterator it = nodes_.find(key);
-		if (it == nodes_.end()) throw(invalid_argument(
-						"BayesTree::marginal('"+key+"'): key not found"));
-
 		// get clique containing key, and remove all factors below key
-		node_ptr clique = it->second;
+		node_ptr clique = (*this)[key];
 		Ordering ordering = clique->ordering();
 		FactorGraph<Factor> graph(*clique);
 		while(ordering.front()!=key) {
diff --git a/cpp/BayesTree.h b/cpp/BayesTree.h
index eeed835f0..bf97f556e 100644
--- a/cpp/BayesTree.h
+++ b/cpp/BayesTree.h
@@ -93,6 +93,15 @@ namespace gtsam {
 		/** return root clique */
 		boost::shared_ptr<BayesNet<Conditional> > root() const {return root_;}
 
+		/** find the clique to which key belongs */
+		node_ptr operator[](const std::string& key) const {
+			typename Nodes::const_iterator it = nodes_.find(key);
+			if (it == nodes_.end())
+				throw(std::invalid_argument("BayesTree::operator['"+ key + "'): key not found"));
+			node_ptr clique = it->second;
+			return clique;
+		}
+
 		/** return marginal on any variable */
 		template<class Factor>
 		boost::shared_ptr<Conditional> marginal(const std::string& key) const;