diff --git a/gtsam_unstable/nonlinear/LinearContainerFactor.cpp b/gtsam_unstable/nonlinear/LinearContainerFactor.cpp
index e6c49b318..b5701fb13 100644
--- a/gtsam_unstable/nonlinear/LinearContainerFactor.cpp
+++ b/gtsam_unstable/nonlinear/LinearContainerFactor.cpp
@@ -38,6 +38,15 @@ void LinearContainerFactor::initializeLinearizationPoint(const Values& lineariza
 	}
 }
 
+/* ************************************************************************* */
+LinearContainerFactor::LinearContainerFactor(const GaussianFactor::shared_ptr& factor,
+		const boost::optional<Values>& linearizationPoint)
+: factor_(factor), linearizationPoint_(linearizationPoint) {
+	// Extract keys stashed in linear factor
+	BOOST_FOREACH(const Index& idx, factor_->keys())
+		keys_.push_back(idx);
+}
+
 /* ************************************************************************* */
 LinearContainerFactor::LinearContainerFactor(
 		const JacobianFactor& factor, const Ordering& ordering,
diff --git a/gtsam_unstable/nonlinear/LinearContainerFactor.h b/gtsam_unstable/nonlinear/LinearContainerFactor.h
index a8f7cd399..324556622 100644
--- a/gtsam_unstable/nonlinear/LinearContainerFactor.h
+++ b/gtsam_unstable/nonlinear/LinearContainerFactor.h
@@ -25,8 +25,7 @@ protected:
 
 	/** direct copy constructor */
 	LinearContainerFactor(const GaussianFactor::shared_ptr& factor,
-			const boost::optional<Values>& linearizationPoint)
-	: factor_(factor), linearizationPoint_(linearizationPoint) {}
+			const boost::optional<Values>& linearizationPoint);
 
 public: