It depends upon how severe the injury is that they suffered. If it was minimal and they didn't get any medical treatment, then it would be very limited, say less than a year. If they did have to get treated, then it could be up to two years. If very severe, then it could be as much as five years, however, none of those times are cast in stone because the longer it goes from the time of injury untiil the time they file a complaint with the prosecutor, the worse their chances are of getting them to entertain the charges.
Check with a local criminal defense lawyer to verify the times.
It depends on the nature of the assault. Was a weapon used? What were the injuries to the victim? The crime charged may not necessarily have the label "assault". The length of time before the statute of limitations bars prosecution depends on how the assault is charged. If the assault is a misdemeanor, the statute of limitations is one year from the incident. If the assault is a felony punishable by 7 years or less, then the deadline to file charges is 3 years. If the assault is punishable by 8 years or more, then the deadline is 6 years.
Someone does not have to "press charges" for the DA to file charges - the decision is up to the DA, although usually someone has to report the incident to the police for the DA to learn about it.
You should consult with an experienced criminal defense attorney - most offer free or low-cost initial consultations. If the assault arose from a domestic violence incident, then even a misdemeanor assault is very serious - a misdemeanor conviction of domestic violence makes it illegal for you to possess a firearm.
Mr. Robinson is DEAD WRONG once again. He is not licensed in California and appears to guess about California law.
First of all, an individual cannot "press charges." Only the District Attorney can file a criminal case. If a crime is reported to the police, they will forward their reports to the DA, who will decide what charges should be filed.
The District Attorney has a limited time to file charges. If the offense can only be filed as a misdemeanor, then charges must be filed within one year. If the offense can be charged as a felony, then the period to file charges is three years or more.
It is NOT necessary for the victim to suffer serious injuries -- or any injury at all -- for assault to be a felony in California. For example, if the force could have caused serious injury, a weapon was involved, it was committed for the benefit of a gang, or you threatened to kill the person, you could be looking at felony charges.
Do not talk to anyone but an attorney about this situation. If contacted by the police, tell them you respectfully decline to speak with them. If arrested, politely, but firmly, tell them you will not answer any questions unless you are represented by an attorney.