That would be the FBI Rex. If you think Comey was out to sabotage Trump, you may recall he helped get the man elected.
In all honesty though, I think by far the biggest problem with James Comey, is that he cares about his image too much. To that end, he has spent his entire career trying to have integrity beyond reproach, and when faced with a decision before the 2016 election of whether to protect his personal integrity or the integrity of the election, he chose himself... Just days before the election, he was presented with information that there may be some more Hillary emails to investigate. Rather than first verifying this to be the case, he just decided to call a press conference to get that information out to the public so that he would never be accused of hiding any damaging information about a candidate. The problem is, that by so doing, he tilted many undecided voters toward Trump, probably enough to tilt the needed swing states. Soon after the election though, it was determined, the aforementioned emails didn't turn out to be new material after all, but rather the same ones the FBI and the public had already known about for quite some time. By calling that press conference, he did enormous damage in the final days Hillary's candidacy, and Trump praised him publicly for it.
It was only after he later refused to shut down a legitimate counter intelligence investigation in to president's administration that he became your apparent enemy. An investigation mind you that has already resulted in several criminal convictions of people close to the president. And an ongoing impeachment inquiry that has already heard testimony of corruption from some of the president's own hand picked political appointees.