Law enforcement agencies, like the local police, can arrest you if they have probable cause. It means they have cause to believe you’ve committed a crime. They can hold you for a few hours or days. Probable cause is based on a strong suspicion. Law enforcement agencies CANNOT charge you with a crime. To be charged with a crime, is something only the District Attorney’s office can do. They are a prosecuting agency, and they are the ones who file a complaint against you in court. For more serious crimes, you can be held without bail. For less severe crimes, you can be released on your own recognizance – which is an agreement that you will return back to court on a specific date. For other crimes, bail will be required for your release.
If after an investigation the detective believes theres enough evidence to prosecute you – he, or she, will bring the case to the prosecutor. The prosecutor will then decide whether to file charges, and what charges should be filed. If you’re in custody, and no charges are filed against you within a few days – you have to be released. The prosecutor has up to 1 year, or more, to file charges.