I would say it's difficult to pinpoint the reason for their selectiveness, but my best guess is the person has a prior violent record is why they disregarded his complaint/report with evidence--which is still no less discriminatory or wrong. More specifically as to what did occur, he first went to the police department directly after being assaulted by his ex-girlfriend, bearing scratches and obvious marks from her hitting him, and the officer there refused to allow him to submit a report and told him to go to domestic relations court the following Monday (true story). He has an actual audio recording of the assault taking place (via a smartphone recording app, converted to audio disc), and took photographs.

About 2 weeks later, she swung her fist at him when he dropped their daughter off to the mother (the ex), and he then went home and contacted police and filed a report after an officer was dispatched, giving a statement as to both occurrences. No warrant was issued nor arrest was made, and he contacted the detective who was assigned with the complaint; he stated he submitted a warrant request and forwarded it to the warrant officer. So, he then went to the courthouse to speak to the warrant officer after calling to find out what the status was a few days later, also presenting his audio and photographic evidence (beyond dispute he was assaulted by her, noting also that she never made a report alleging he assaulted her). The magistrate had initially denied issuing a warrant. The file was supposedly submitted to the magistrate who issues warrants afterward, for a second review, and he called a week later and spoke to the warrant officer yet again, who told him the magistrate is not issuing a warrant or pursuing criminal action.

That was separate from the protection order violation dismissal, and there was no protection order in place at the time of the assault. Clearly he was wronged, for had she been prosecuted, the latter events (which have not been discussed) would have taken a drastic turn. So, what is his best recourse?