UIGestureRecognizer - detach SKSpriteNode after dragging - ios

Question

I am using UIPanGestureRecognizer to rotate my sprite nodes with one finger (i.e. dragging the sprite up rotates it clockwise, and down anti clockwise).
This is my piece of code that works for the above function
let gestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
self.view!.addGestureRecognizer(gestureRecognizer)
handlePan(gestureRecognizer)
func handlePan(_ gestureRecognizer:UIPanGestureRecognizer){
if gestureRecognizer.state == .began {
var touchLocation = gestureRecognizer.location(in: gestureRecognizer.view)
touchLocation = self.convertPoint(fromView: touchLocation)
gestureRecognizer.minimumNumberOfTouches = 1
self.selectTouchedNode(touchLocation: touchLocation)
}
if gestureRecognizer.state == .changed {
var touchLocation = gestureRecognizer.location(in: gestureRecognizer.view)
touchLocation = self.convertPoint(fromView: touchLocation)
var translation = gestureRecognizer.translation(in: gestureRecognizer.view!)
translation = CGPoint(x: translation.x, y: translation.y)
self.rotateNode(translation: translation)
}
if gestureRecognizer.state == .ended {
selectedNode.removeAllActions()
}
}
func selectTouchedNode(touchLocation: CGPoint) {
let touchedNode = self.atPoint(touchLocation)
if touchedNode is SKSpriteNode{
selectedNode = touchedNode as! SKSpriteNode
print ("touched")
} else {
selectedNode.removeAllActions()
}
}
func rotateNode(translation: CGPoint) {
selectedNode.zRotation = translation.y * 0.01
print ("Rotate")
print (translation.y)
}
However, my sprite nodes becomes "sticky" after I drag, i.e. if i've dragged sprite1, dragging the background of the scene still rotates sprite 1 until i drag sprite2, which then rotates sprite2 until I drag another node.
How can I "detach" the nodes so that it only rotates when I start the drag on their position?