When authorities arrest and take a suspect into custody, they typically set bail according to a pre-established schedule. There's no discretion involved—the agency holding the suspect (oftentimes a sheriff's department) simply sets bail at the amount designated for the alleged crimes.
If the suspect—or, more likely, a friend or family member—can afford bail and posts it, temporary freedom awaits. But bail can be tremendously expensive, even through a bondsman. That's why many defendants ask the court to either lower bail or grant own-recognizance (OR) release at a bail hearing.
At a bail hearing or sometimes at an earlier hearing (like an initial appearance), the judge will evaluate any predetermined bail amount and decide whether to change it. If so, the judge needs to figure out what amount is reasonable to make sure the defendant shows up for future court appearances.
Being released on bail or OR release means the defendant remains free in the community pending trial. Judges want to make sure defendants come back to court and don't commit more crimes or harm others while out on bail. They must balance these concerns with the defendant's presumption of innocence.
The first time a judge takes up the issue of bail is often informal: Discussing the relevant bail factors, the prosecution and defense each make a quick pitch for increasing bail or keeping it as is on the one hand, and lowering it or granting OR release on the other.
Specially designated bail hearings tend to be relatively informal. But consideration of "ex parte" evidence—evidence from only one side without the other present—is generally improper. The judge will consider arguments from each side and may even choose to hear witness testimony.
Regardless of the format, the bail hearing allows a defendant to hear and respond to the government's presentation at a hearing that is open to the public.
The issue at a bail hearing isn't the defendant's guilt or innocence, but rather the likelihood that the defendant will behave properly and return to court as necessary if released. Generally, the court may consider the apparent weight of the evidence against the accused. But this isn't the primary consideration, and the judge isn't normally supposed to make findings about the facts underlying the case.
Different jurisdictions have different rules when it comes to bail reviews. Some states allow defendants to have bail reviewed if they can't afford to post bail and remain incarcerated for a certain length of time. Other circumstances that might justify a bail review hearing include a lengthy trial delay, new evidence relevant to bail determinations, or a constitutional challenge. Typically, the same judge who presided over the initial bail hearing will conduct the bail review hearing.
If you have, or someone you know has, been arrested and is awaiting bail, consult an experienced criminal defense attorney. That lawyer will know the workings of the local bail system, both in and out of court.
And having a lawyer argue the issue of bail is a much better option than the defendant doing so. The lawyer can also arrange for the appropriate friends, family members, and associates to come to court. For example, a lawyer might arrange with a roommate to show up and attest that the suspect has a place to stay upon release.