If you watch basically anything (especially period pieces) the Irish as police is a well-worn trope. Is this a real phenomenon? If so, why did the Irish of all people get so involved in policing, and if not, where does the stereotype come from?
here's a link to a previous AskHistorians thread, "Why and how are Irish culture and the culture of police/law enforcement so closely related in the United States?" in which u/Searocksandtrees links to a comment by u/snackburros about why there's a pervasive existence of Irish police officers in American police forces.
Next, in the context of anti-Irish prejudice, u/iresentthat answers how the role of Irish-americans in policing grew with the expansion of voting rights and the bloc voting of concentrated urban irish immigrants:
/u/mimicofmodes has more information in that thread on irish employment opportunities that led to the association with the firefighting and later policing trades.