private void checkHit()
    {
        TouchCollection tc = TouchPanel.GetState();
        /* // Write the touch location to debug
        foreach (TouchLocation tl in tc)
        {
            if ((tl.State == TouchLocationState.Pressed)
                    || (tl.State == TouchLocationState.Moved))
            {
                Debug.WriteLine(tl.Position.ToString());
            }
        }
        */ // End of touch debug checking
        if ((tc.Count > 0) && (tc[0].State == TouchLocationState.Pressed))
        {
            Point touchPoint = new Point((int)tc[0].Position.X, (int)tc[0].Position.Y);
            foreach (Sprite s in Sprites)
            {
                if (s.SpriteRectangle.Contains(touchPoint))
                {
                    s.isAlive = false;
                    return;
                }
            }
            /* // replaced with code above for simplicity, same problems occur
            for (int i = Sprites.Count - 1; i >= 0; i--)
            {
                Sprite sprite = Sprites[i];
                if (sprite.SpriteRectangle.Contains(touchPoint))
                {
                    sprite.isAlive = false;
                    break;
                }
            }
            */
        }
    }