Pop star Michael Jackson’s secret indictment on child sex charges has set the stage for a unique defence challenge on grounds that the extraordinary security measures may have intimidated witnesses and grand jurors.

Dozens of prospective grand jurors arrived at an assembly room so court officials could begin selecting a panel to hear evidence in the child sex abuse case against Michael Jackson.

On the eve of grand jury hearings in the Michael Jackson molestation case, a judge barred pictures or communication with any prospective or final panellists, or grand jury witnesses.