No, a complaint was made by a member of the public - presumably malicious communication, which is a criminal offence.
Not sure if it meets the threshold for a criminal conviction, but in theory the police have to investigate every complaint and given the profile of it, hence why they are being a bit speedy investigating it.
I mean his career and social standing are ruined. But going any further than firing him just seems nuts. I mean we get terrorists (of all nationalities and religions) not being investigated and this guy is just an idiot at best and non-violent racist at worst...money better spent elsewhere. His life is in the crapper now anyways...he's going to suffer plenty.