Let's say someone sees me sneak a sword into the city of Rome. Who do they tell about it to officially get me accused of a crime by the state? Who tells me I'm being accused of a crime, and what happens to me when I am? What happens to me after the trial?
Hello there. Not discouraging anyone from providing additional information, but do check out these older answers :
How did republican Rome function without a police force? by u/XenophonTheAthenian
Before the formation of the Praetorian Guard, who would Guard and Protect the Senators, Consuls etc. in Rome? by u/XenophonTheAthenian
Hope this helps.