Mangione walked into Manhattan Criminal Court, shackled and wearing tan prison clothing, shortly before 9:30 a.m. for the hearing on several pre-trial motions. Members of the press and the public packed the courtroom, while crowds of his supporters carried signs and chanted outside. 

When he entered, he appeared to look at the rows of public in the back very briefly, then stared straight forward. As he left, he raised his eyebrows in acknowledgement -- once at the defense's first row in the gallery, and then again as he walked past the press and public. 

His supporters were later seen following his attorneys down the street as they left court. 

Luigi Mangione's terrorism charges thrown out

The 27-year-old faces both state and federal charges in the killing of Thompson, a husband and father of two, last December outside a Manhattan hotel. The 11 state charges included murder and terrorism, and the federal ones carry the possibility of the death penalty.