Delincuente

In English, the noun 'delinquent' often refers to young lawbreakers, 'juvenile delinquents'. In Spanish, delincuente is more general, refering to someone of any age who is engaged in criminal activity, a criminal. (The word 'criminal' does exist in Spanish but it is less commonly used than its English counterpart.)

Crimes are delitos. (Again, crímenes exists but is less used than its English counterpart.) A felony, a crime with serious legal consequences, would be a delito grave. When speaking of crime in general and not of specific incidences, use delincuencia. High rates of crime, altos niveles de delincencia.

An asalto is a mugging or a hold-up, so it doesn't work as a general translation for the English word 'assault'. Esto es un asalto. This is a stick-up. Me asaltaron en la calle. I got mugged. An asaltante is an attacker. Atracar is another common verb for 'attack' criminally.

A ratero is a garden-variety thief or robber. I've also heard ratero applied disparagingly to white-collar offenders engaged in corruption. Speaking of corruption, the noun 'bribe' is mordida, literally 'bite', or more formally, soborno. The corresponding verbal forms are dar una mordida and sobornar.