How can a warrant be issued without physical proof? On just the word of another person.
2 attorney answers
You have to understand the difference between two distinct concepts: "probable cause" and "guilt."
The police must have "probable cause" to arrest someone. Probable cause means that there is sufficient evidsence to BELIEVE that a crime MAY have been committed, and that the person who is arrested MAY have committed the crime. Probable cause is a fairly low standard, and it can be based on nothing more than the statements of a witness (like the girlfriend). Even if the witness is lying, unless the police have a reason to believe she is lying, they can act on the witness's statements.
"Guilty" means that a jury (or a judge, in a bench trial) has found that there is sufficient evidence to prove BEYOND A REASONABLE DOUBT (BARD) that the defendant committed the crime with which he was charged. That's a very HIGH standard of proof.
When you hear the phrase "Innocent until proven guilty," it's referring to the latter concept, which can only occur after a trial (unless the defendant admits his guiilt in order to accept a plea agreement).
In the situation you described, it appears that the police and prosecutor determined that there was probable cause to file charges against your son. Now, the State will have to prove BARD, that your son is guilty. If they can't, then he will be acquitted.
I'm licensed to practice law only in Indiana, and we've never met, so I can't give you "legal" advice. My answer is simply "friendly" advice based on my experience as an attorney in Indiana, my knowledge of federal and common law, and common sense. Even if you are in Indiana, employment law questions are very fact specific, and based on the limited information you provided in your post, I can't give you legal advice, and my answer is intended as general information only. It doesn't create an attorney-client relationship.
Most likely your son can bond out, pending his trial. If the bond is too high, he can ask for a reduction. He does need a defense lawyer to help him