Anthony's father, George Anthony, is expected to be one of the witnesses, a source said. Typically, detectives are called to speak before the grand jury.
How does a grand jury work?
People who have drivers licenses or state identification cards are selected at random to serve on grand juries.
They are allowed to ask witnesses questions and, if needed, ask to hear from specific witnesses. However, the state cannot force Casey Anthony to testify if she doesn't volunteer, and prosecutors must also question any witnesses who can offer evidence that could clear Anthony.
The state has to prove only probable cause to charge Anthony with a crime. Proving a case beyond a reasonable doubt is the standard for a criminal trial.
Is the grand jury open to the public?
No. What happens before a grand jury is secret. By law, witnesses, jurors and prosecutors are not allowed to talk about testimony. If they do, they may be held in contempt of court.
The media is not allowed in the grand jury proceedings. This is to ensure the witnesses and jurors are free from outside pressures.