District Attorneys also aren't part of the judicial branch, they are part of the executive branch, but they are still the ones prosecuting crimes in court.
What happened is that Navarro was told to show up, didn't, and Congress went 'this guy is insulting us by ignoring us', told the executive that he is 'in contempt of Congress' by doing so and asked the executive to prosecute the crime. Which it did. In a judicial proceeding before a federal judge.
What happened is that Navarro was told to show up, didn't, and Congress went 'this guy is insulting us by ignoring us', told the executive that he is 'in contempt of Congress' by doing so and asked the executive to prosecute the crime. Which it did. In a judicial proceeding before a federal judge.