Program crashes after running for a few seconds/mins--issue with push_back()

Hi

I'm drawing lines between two markers in osgart. So whenever they are moved, the lines are updated each time.

For this I'm updating an 
Code:
osg::ref_ptr<osg::Vec3Array> points

My program crashes after it is run for a several seconds/minutes. I found out that the following lines cause
the issue (commenting those can avoid it)

Code:
points->push_back(StartPoint); 
points->push_back(EndPoint);

I assume it is due to a memory leak, eventhough I use points->clear() at the end.

Here's my code (please note that some lines have been omitted for clarity)

Code:
class CallBackClass: public osg::NodeCallback{

private:
	osg::ref_ptr<osg::Vec3Array> points; 
	osg::ref_ptr<osg::Geometry> beam; 

public:
	CallBackClass::CallBackClass(){
		points = new osg::Vec3Array; 
		beam = new osg::Geometry;