Let's not overstate things here. There's a reasonable amount of evidence that there were efforts to slightly underinflate footballs and that Brady knew about it.
No, there actually isn't. The decrease in pressure is adequately explained by environmental factors. There is in fact little or no chance a person intentionally deflated the footballs. When you take into account the temperature and dampness, the person doing the deflating would have to remove such a tiny, insignificant amount of air that it would a) be impossible to do with a crude needle and b) imperceptible by Tom Brady.