A parole officer is a person who supervises convicted criminals after they are released from jail on parole.
Parole officers are responsible for making sure that the offenders comply with all legal requirements as they begin transitioning back into society. If an offender fails to comply, then a parole officer can recommend that they go back to prison.
If a parole officer recommends that a person be sent back to prison due to violating the terms of parole, then there is a very good chance that they will be sent back.
Parole officers are very similar to probation officers. The main difference is that parole officers supervise people who have been in prison, and probation officers supervise people who were put on probation instead of being given a prison sentence. However, both supervise people who have found themselves facing punitive consequences of unlawful behavior.