Luigi Mangione Sick, Hearing Canceled

Luigi Mangione's critical hearing in his state murder case was put on ice Friday, because the defendant's under the weather.

Judge Gregory Carro made the announcement just as court was set to begin Friday ... saying Mangione had fallen ill. The judge said the hearing will resume Monday.

We got LM's defense heading out of the courthouse -- dressed their best to impress the judge -- but they were mum as to what was ailing Luigi.

Mangione's pretrial hearing in the New York state case began Monday ... with the alleged killer leaving behind the confines of MDC Brooklyn for an NYC courtroom where he was photographed chatting with his lawyers -- looking put together in a nice suit sans tie.

Prosecutors have played the body cam footage of Luigi's arrest following the shooting of UnitedHealthcare CEO Brian Thompson at a McDonald's in Pennsylvania ... during which he allegedly gave cops a fake I.D.

The defense is asking the judge to exclude that and other evidence, on ground Luigi wasn't given his Miranda rights.

The 911 call, which led to Mangione's arrest, was also played in court ... with the caller saying multiple customers told her he looks like the guy who shot Thompson.