05/25/2011 AT 05:45 PM EDT
Jared Lee Loughner is not mentally competent to stand trial on charges he killed six people and wounded Arizona Congresswoman Gabrielle Giffords, a federal judge ruled on Wednesday.
Based on court-ordered medical evaluations, the judge determined Loughner was incapable of understanding the proceedings, according to CNN.com
The 22-year-old has been described as "gravely mentally ill" by his own legal team.
The decision came after Loughner was removed from the courtroom following an outburst in which he reportedly said, "Thank you for the freak show. She died right in front of me."
Loughner is charged with killing six people and wounding 13 more, including Giffords, during a shooting rampage in Tucson
on January 8.
The judge ruled that Loughner would remain in custody and undergo treatment for the next four months. A hearing has been set for September 21 to determine whether his condition has improved enough for proceedings to resume.
Giffords, who is recovering from a gunshot wound
to the head, recently attended the launch
of Space Shuttle Endeavor, commanded by her husband Mark Kelly.