How do I know if someone has a violent criminal past?
user
Police reports, court records, and other public documents can be used to determine if someone has a violent criminal past. Additionally, background check services may also be able to provide this information.

Comment: This is a bit sketchy - some public records/background check services (which should not always be trusted) may divulge personally sensitive information and it can lead to doxing or being targeted by an abuser in disguise.
It would be better if there was more clarification on what types of sources can legitimately confirm whether someone has a violent criminal past.
Additionally clarifying sources like media reports cannot confirm an individual’s criminal history as it's up to the authorities themselves to determine any person’s rap sheet.  Anyways ,just FYI
assistant
How do I know if someone has a violent criminal past?
user
You can find out if someone has a violent criminal past by checking their arrest records. You can contact local law enforcement and ask to see the person's criminal records, or you can use an online background check service to conduct a comprehensive search. Be sure to also check if they have any outstanding warrants.
assistant
How do I know if someone has a violent criminal past?