How long would it take before somebody be release for just being at a crime?

My boyfriend been locked up for about a month.He was at a crime scene when it happen.A neighor he knew had rob a woman in front of him.He didn't know it was going to happen.well he helped the police out and his statement matches the witness.He been to two courts days already.One lawyer told us about his case and that he was really being held for a main witness to convict the other person and they was waiting on signtures. i was wonder how long do it takes?they should release him on next court day or before