When police arrest a suspect who is then convicted of the crime, it is a rare exception rather than the rule in the US.
— Read on theconversation.com/police-solve-just-2-of-all-major-crimes-143878
Commentary: How can the Criminal Justice System be this massive trap of Mass Incarceration when only 2% of the crimes that carry the longest prison sentence end in conviction. I’m not sure how plea deals are calculated seeing that 90% of all court cases end in a plea deal. Some of the thoughts here are that criminals are prolific and they eventually get caught, so the arrest of one criminal may stop 20-30 future crimes. Some criminals commit very few crimes and stop either forever or for long periods of time.
NOTABLE: Publications from the links in the article
How Effective Are Police? The Problem of Clearance Rates and Criminal Accountability
Most violent and property crimes in the U.S. go unsolved
Alternatives to Arrest for Young People