If someone does a crime but there was no law against it at that time, do they get caught if a law is set up for it in the future?

Question

So for exemple if someone got on with a minor at the past, or if someone was openly racist in the 50s, would they be jailed now if they were alive, or do laws apply to the time you commited the crime?

In: Other

Answer 1

A law that puts penalties on prior behaviors is known as an ‘ex post facto law’ and many jurisdictions have constitutions, charters, or other foundational documents which outright ban such laws – In the United States at least, such laws are banned both federally and on the state level by the constitution so a law cannot criminally penalize behaviors prior to the passage of said law.