Complex sentence: In fact, according to Frances FitzGerald, there was absolutely no evidence that such research was being carried out, what had really changed was that Teller was now selling his latest nuclear weapon, the X-ray laser.
Split into simpler sentences: In fact, according to Frances FitzGerald, there was absolutely no evidence that such research was being carried out. What had really changed was that Teller was now selling his latest nuclear weapon, the X-ray laser.