Particle system leaves trail while being stopped

Hey, I’m making particle effect which follows users touch on Android. When I rise my finger and touch screen elsewhere, particle system makes sparse trail between those two points. Any idea what’s the matter?
(Don’t mind the ugly if around .Play() - it’s just for particle system to not write on my button)

			if(Input.touchCount>0)
			{
				Touch touch = Input.GetTouch(0);
				ray = Camera.main.ScreenPointToRay (new Vector3(touch.position.x,touch.position.y,0));
				particleSystem.transform.position = ray.GetPoint(3);

				if(touch.position.x>myGUI.btnSize+myGUI.btnOffset||touch.position.y<Screen.height-myGUI.btnSize-myGUI.btnOffset)
				{
					particleSystem.Play();
				}
			}
			else
			{
				particleSystem.Stop();
			}

It looks to me like you should only be playing your particle system if both of those conditions are true, and otherwise not.

if(Input.touchCount > 0 && (touch.position.x > myGUI.btnSize+myGUI.btnOffset || touch.position.y < Screen.height-myGUI.btnSize-myGUI.btnOffset))
{
	Touch touch = Input.GetTouch(0);
	ray = Camera.main.ScreenPointToRay(new Vector3(touch.position.x, touch.position.y, 0));
	particleSystem.transform.position = ray.GetPoint(3);
	if (particleSystem.isStopped)
		particleSystem.Play();
}
else if (particleSystem.isPlaying)
{
	particleSystem.Stop();
}