A friend of mine has been a policeman for many years. He's lost count of all the times he's been called to court to give testimony about evidence found at the crime scene and on the person of the one arrested for an omnibus hearing. Sometimes a forensic expert will testify also, if the crime scene is complicated.
During the omnibus hearing, the prosecution and the defense must share what they know about the case so the trial can be fair. If they need more time to gather evidence, they get it. Neither side can pop up with new surprise evidence when the hearing is over.
In my opinion, we do have a really "slick" legal system!